You found a new map, and wanna learn map before you play it on server.
1. Open Wolfenstein ET
2. Open console and enter
The word "map" stay for the name of the map you wanna play.
You find the current mapname inside your PK3-file (PK3 are simple ZIP-Files). Open file and look into folder /maps. The name of the map is the name of the *.bsp-file.