@NO U since no servers are hosting it the easiest way is to open the developer console using the ~ key (You have to enable it in settings -> keyboard -> advanced) and type in "map koth_sawhell"

To play the server with bots (which are pretty bad about not dying to the sawblades) you can type in "tf_bot_quota X" where X is the number of bots you want total.

If you want friends to be able to play with you one of you would have to learn how to port forward. There are tutorials under guides on steam that can help you do that if not on YouTube/Google.

looks like hell to me, how do i join/ start up the map?