...and now I have to install or configure anything on this site?
Yes, but i don't have a "todo list" for you.
If you are a webmaster, you will have no problems with javascript mysql and php webcode
All my experience and knowledge are also from god google
Maybe there is a little bit more info inside this thread
what does "But you can't "search" for him", because we play close to each other
In this case it's not important for you.
what "you can't follow him (fixing the cursor on his icon)"
their position on the map is not updated?
The cursor (cross in the map center) can't following his position.
Of course, you will see his new position icon after auto refresh time.
What ever, I think paintball is too fast for looking where is your mate

and the server/data connect is too slow..
So I recommend you to test on Locus Testserver...