When you create a new project, each wall has a height of 270 cm. (approx. 8' 10").
If you want to change the walls' height, follow these steps:
- Open the 3D View, in order to focus on any wall of the project
- Click the mouse (or tap your finger) on the wall
- Look at the Property Window (it is in the right side of the screen, as you can see in the image below): from there you can specify the new height of the wall. Then confirm by clicking Apply
- This way you change the height of all the walls of the room
Note: it is not possible to change the height of specific walls. Use small wall command if you want to represent walls with a lower height