First of all, I don't think you are an idiot at all. I think your questions are very valid. Most of us had to start somewhere before we knew how to take care of our hair. That's what this board is for.
Some tips for washing your hair at home:
Do a hot oil treatment before you shampoo. I have done hot oil treatments on both dry and wet hair. The results are nice either way, but definitely more noticeable on wet hair. (If you don't want to have to get in the shower to wet your hair before applying the oil, you can use a spray bottle full of water to spray sections of your hair and apply oil to each section after it is wet. I like this method because I can mix things in the water like msm or essential oils) A good oil to use is Olive oil. Extra Virgin seems to do more than the others (but this is my opinion. I think it has something to do with the process of making the oil. Extra Virgin means that he olives have been pressed once and the oil is taken from them. The other types are from when the olives have been pressed and distilled and depending on how much they have been distilled the further away from the olive you get- which is why extra virgin has a stronger taste and smell than the others. ( you probably didn't want all of that info, but I learn some of the most interesting things where I work and tend to share them with whomever will listen)). Now with a hot oil treatment you can either heat the oil and then apply or apply and then heat using a heating cap, dryer, or hot towel. However you heat, make sure you have a plastic cap over your head to keep the heat on your hair.
Once you have done a hot oil treatment, you can shampoo. Be very careful. The trick is to keep your hair in one direction (this will help with tangles and will keep it straight). The best place to wash your hair is in the shower with it all facing towards the back. Which is kind of funny because I usually end up in the shower at least two times (rinse the hot oil and shampoo, then to rinse the deep conditioner) I think some of the other ladies have given some recommendations for shampoos on this board- some ladies even make their own. You can also wash your hair with conditioner- do a search on this site for more info on that. Once you have rinsed the shampoo (making sure that you have thoroughly rinsed those neglected areas in your kitchens and behind your ears), you are ready to condition.
Depending on your hair's condition you should use either a moisturizing or protein conditioner. IF you use a protien conditioner, follow it with a moisturizing one as protein will dry out your hair with continued use. Now, you don't have to go out and buy brand new conditioners especially if you are just starting up a routine. I have found that adding Extra virgin Olive Oil and Honey will boost the moisture and shine factor in practically any conditioner. (If you are a pj like the rest of us you probably have several discarded conditioners around your bathroom already). When you deep condition it is a good idea to use heat, although many ladies will simply add the conditioner and put on a plastic cap and let their body heat do the rest. IF you are pressed for time any of the same methods for applying heat to your hot oil treatment will work with deep conditioning as well. YOu want to deep condition for at least 15 minutes although I usually go at least 30 minutes usually an hour. (My hair has major issues with dryness so I tend to always do an hour once a week at least).
As far as styling, you want to use moisturizing products especially while your hair is wet (this will help with the comb out). Your goal whether your hair is wet or dry is to always have as little hair left in the comb as possible (Always check the comb when you go to a salon to make sure they haven't pulled your hair out while styling). You want to use things that will give your hair as much "slip" as possible because your hair is in its most fragile state when it is wet and when it is completely dried out. A really good leave in for wet hair is Profective break-free. I swear by this stuff for my comb outs.
The majority of the salon look is in the set. IF you get regular roller sets at the salon, pay attention to how they are done and then practice at home on dry hair until you feel confident enough to try a wet one. If you already know how to wrap your hair you are doing better than a lot of us were when we found this board.
Roller Sets: They are by far my personal favorite for a wet set. but they do take time and patience. IF you don't think you can be in a patient mood when doing your hair you may be better off finding someone who can do them for you.
Pony Tail Sets: These are great if you don't have time to really set your hair (Especially after the hot oil, shampoo, and deep conditioning). Do a search for ponytail method on this board and you should be able to find instructions. If you have a good bit of new growth you can set your hair in multiple pony tails to get the root straight. Just remember that the goal of the pony tail is to straighten the roots by holding the hair firmly in one direction. Don't make the ponytail too tight or you will end up pulling your hair out at the edges. Try to use a ribbon, or an elastic that doesn't have metal clasps on them something smooth is always best so that your hair does not get snagged on them.
Wrap Sets: I love the way wraps look, but I myself don't look good in the traditional ones. My hair is too bushy at the crown to lay down properly and tends to get matted. So, I usually will ponytail or bun the crown and wrap the rest.
In the end, its about your hair and what works best for it. Surf this site, there are some very good advice and some great tips and recommendations here.
As for Vitamins, they aren't necessarily for everyone. I have noticed that they help with not only growth but keeping hair on my head longer. If you are worried start with a basic routine. A multivitamin is always good. I also recommend Ultranourishair by GNC. UltraNourishair already contains many of the vitamins that some of us take in single doses (msm and biotin for example), so if you are going to have any side effects you will notice them from the Ultranourishair and you can adjust your single intake accordingly. You are not by any means required to take them for the rest of your life. However, you will notice a gradual difference if you stop taking them for a while - for me it was increased shedding. Now if you have problems with dry hair, water is key. I don't mean just putting it on, but drinking it is important. I don't know how true it is about the 8 glasses a day. I think that is more dependant on the individual, but if you are noticing that your skin and hair are really dry, or if you constantly have chapped lips, those are small signs of dehydration and should not be ignored.
Sorry this is so long, I hope I was able to help. Feel free to ask any questions, and welcome to the board.
