Used to know how back when making dod maps. But i believe tf2 is a bit different. How do i make water, what function it is anyway. And how do i make intel instead of cap points.
Water is the same as all source games, use a "nodraw" brush and texture the top with the water you want, then put a cube map at eye level above it.
As for intel, you need two things, an entity "item_teamflag" set to the team you want, and a "nodraw" brush set to "func_capturezone" around the area that you want the flag to be.
Heres a tutorial from the Source wiki on doing CTF too: http://developer.valvesoftware.com/wiki/User:Daeval/TF2_How_To_Setup_Capture_The_Flag