Is it possible to play this single player? Kind of like how you can start your own LAN server in Paintball 2 and play by your self?
Once you've gotten all the necessary files and placed them in the right place, either by doing what jitspoe said or by connecting to the icey's jump mod server (if you connect, you'd have to manually move the maps to paintball2/jump/maps), then you can play the mod offline. First, you have to run the mod (type: game jump), then you choose whatever map you want to play (type: map ariejump47) and play.
Normal paintball2 jump maps do not work as they should on the q2jump mod, but most of them have been fixed to some degree on icey's jumpmod server. To get them, you'd have to play all of them on the server.
Here are some commands you should know though.
!help this command will show you some commands that you can use
maplist # you can see what maps the server has, the # signifies a number
score you can see your times with this
cl_hudstyle 0 will make the game use the correct hud
team easy makes you play on the practice mode
- store saves your location
- hook/unhook hook to shoot, unhook to release. Good for changing your location
team hard use this mode once you want to get a time
kill will make you restart from the start or the storepoint
inven opens the menu, use the [ and ] keys to choose stuff
Edit: Spelling mistakes etc.