Hello, the method for making a chamfer is shown as follow:

1. Draw a retangle/squre on the wall(draw method/offset method)

2. Select the rentagle/square area(it will turn in to blue)

3. Go to the right panel to find the chamfer function, select the angle you would like to chamfer

4. Select the chamfer type and outer fillet value, hit enter key to change the outer fillet value