Chemistry 101, or whatever you are taking, will be your best bet to learn the theory behind Chemistry. That being said, if you don't
want to take the class and just do reactions in your garage, youtube works great for that (then you really don't learn much...). Buying a textbook is
by far the best thing you can do for yourself. Learn the trade!
Once again, just doing reactions isn't going to teach you anything. There are millions of people that have worked hard to create the field of
Chemistry and develop the theory. At least pay them the credit of learning it, rather than, "cool it changed colors/made fire for some reason".
That being said, and of course shameless self promotion, look at my signature for a link to the home chemistry textbook project I am working on with
Bromic Acid and plenty of other members on this forum. This will most certainly point you in the right direction of how to learn Chemistry and
hopefully further inspire you.
I will warn you in advance, this book is a work in progress! I am currently working through it and this is a painstaking process. Please do not
blindly follow anything published in the book; it is not an excuse for poor planning/research.
Enjoy and let me know what you think! Updates will hopefully be posted weekly!