can you point me to a link of co2 setups as well as some good fertilizers?

I have gravel substrate as of now with natural river rocks as hiding places and decor (properly cleaned of course), so do I need a different substrate all together or can I put something else over it?

As far as plants (to give you an idea) I am probably only going to look at a couple different ground covers (such as dwarf hairgrass, one of my favs) (leaving the rocks exposed) and some taller plants for the back as well as some medium plants between the rocks. I don't want an extremely grown tank. I normally like the look but I am going for something a little different. I have a GBR right now. Idk if they are plant nippers but I have to plan for that as well. I plan on getting one other ram. I am hoping for a golden ram to pop up at one of my LFS's. (unless mixing the two is a bad idea? I have a lot of hiding places but I don't want to freak them out... I just love them so much lol)

Anyway, hints, tips, suggestions, it's all welcome. Thanks again!