Best thing you can do is read a lot, here on this forum and also on the web in general. Read, think, and then go out and get yourself something better than a little seedling or two. Especially look at the "best trees for beginners" article, and the "nursery collecting 101" article. That way, you will have something that you can work with, within a reasonable time.
Those little kits and things are fun, for gifts, but if you want to really enjoy creating bonsai you need to think....a little bigger.
Welcome, and hopefully you will enjoy it enough to stick around!!
Joanie