to answer your questions, start with 'the basics' of magick and your path, such as meditation, energy work, circle casting and so on. if you're Wiccan things like The Rede, tools, and holidays might be good to learn as well, but each path is different so i can't say exactly what you should study. you should do your year and a day ceremony where you studying everything before decided to convert. if you are planning a religious path over just casting spells. in either case i would take some time to study before casting, say a month of hard studying.
some of the spells on here do work, but many are fake and non-working. magick is energy found in nature, as such it can only do things that are naturally possible, so transformation, invisibility, and flight [to name a few] cannot be done. as mentioned above, study before casting.
not all spells need supplies, the energy you bring forth is what's most important, supplies such as candles, herbs, athame, wand, and so forth are to help with charging more energy. you can cast a spell with no items, but sometimes they're key, like a healing potion without any herbs, or a luck charm without the charm.
over all, i'd study. i don't know your path so i can't help you in terms of books, but look for some articles on the basics.