To place a drain, follow these steps:

1. Go to the Wall drawing tab and find the Drain:
   
   
   
   
2. Left-click & release to select the tool.
3. Move the cursor to your drawing. The drain will automatically snap to the wall. Left-click when you have found the desired point on the wall to place your drain.
4. Enter the desired distance from the wall (length), and the angle in the properties box that appears:
   
   
   
   
5. Finish placing with another left-click or hit Enter on your keyboard.
6. Once you are finished, hit Esc on your keyboard, or move your cursor outside of the drawing area to escape the command.