About "dedicated" servers: yes, you need a tool to host those, but the one in the Steam Library (the one Nik directed you to) doesn't exactly work that well for me. I have to manually download the HLDSUpdateTool (
http://storefront.steampowered.com/download/hldsupdatetool.exe), and then I usually install it to C:\SRCDS. After that, I use Command Prompt to navigate to the directory, and then run the real update tool like this: hldsupdatetool -command update -game tf -dir . (the dot represents the current directory.)
After that, the Update Tool takes a while to download everything. When it finally finishes, navigate to tf\cfg, and modify server.cfg how you want (ex. "hostname" followed by what name you want would set the name of the server as it would appear to players, sv_region 1 would set the server browser region to West Coast, meaning your server will show up when people search for servers on the west coast).
After that, launch SRCDS by going to where you downloaded everything to, and use the following command: srcds -console -game tf -port 27015 (make sure that port is forwarded) +maxplayers (whatever you want to be the max playercount goes here) +map ctf_2fort (any map that's in the server's tf\maps directory can go here). After THAT, it should be working, and it should show up on the Server Browser.
Beware, though. If you're on a home internet, any more than 4-10 players, depending on your internet, will cause either the server's connection to start choking, or your client-side internet to start choking. Make sure you have acceptable upload speed for this (I read somewhere 15 kb/s per player is acceptable).