Downloaded Dedicated TF2 Server off of Steam, how do I...

[The Asylum]

..get a custom map available to play? All I have to choose from are the stock maps :/

[Icarus]

Put custom maps into the dedicated server's /maps/ folder

[The Asylum]

Thanks. Also, when I'm trying to connect to my server, it tells me "STEAM Validation Rejected."

:/

[fubarFX]

means your server isn't up to date

[The Asylum]

How am I supposed to update it? OR does it do it by itself eventually?

[MjRNuT]

The same way you downloaded the files in the first place. Re-run that batch file.