Visit all of these links!
When you click Run Map, you can use these useful commands in "Additional Parameters":
-dev -toconsole -console +sv_lan 1
I used a func_door brush-entity. Click here for 3kliksphilip's doors tutorial
Want to learn all the useful keyboard shortcuts? My keyboard shortcut video tutorial
Like the map in my desktop wallpaper? You can download it here.
***** Notes *****
For the "Z" mouselook toggle to work, your mouse must be in the 3D viewport area when you press Z. When Hammer starts up make sure that the 3D camera view is set to "Shaded Textured Polygons" (Click "camera" in the top left). If you want to centre the four viewports so that each takes up a quarter of the screen, use Ctrl+A anywhere.