Maplestory

how do you make a game like maple tower with multiple characters?

what format should it be and what do i have to download
and how do i use it

things i do know how to use :
bannedstory
paint
windows movie maker (irelavent XP)
the internet O.o

so uh will som1 give a push start XD

thanks every1

i hope to see my game on this site when its done.....