When I add a sprite it replaces the previous one I just added before that. How do I add a sprite while keeping the ones I already have added?
Um... use the next sprite.
sprites.select 0
sprites.select 1
sprites.select 2
sprites.select 3
sprites.select 4
sprites.select 5
etc...
don't think theres an upper limit but if there is its either 8, 16, 32, 64 etc. It's bound to be something pretty high though.
The more effort you put into youre sky the better the maps will look. ALWAYS do sky and lighting first, and add tweaks later when mapmaking. I learnt this the hard way.