Just hit create a server and select the map OR open it in the console with the command:
map cp_gorge_event

(Assuming that's the map's file name.)

If you want to play with bots enter these commands:
sv_cheats 1
nav_generate
(Server Restart)
tf_bot_add <team> <class> OR tf_bot_add 23

Hope this helps.

thanks so much but it i can't find it when i try to create the map or even when i type it in the console it says that the map is invalid or can't be found. :(