You can subtract boolean sketch objects from which another sketch
object.
Context:
When you subtract Boolean sketch objects, the first sketch object you
select is the target object. The target object is the object from which another
sketch object (tool object) is subtracted.
In the
work area,
select the target sketch object.
In the
work area,
press
Ctrl and select a sketch object that overlaps
the target sketch object.
From the
context toolbar,
click
Subtract
.
The tool object is removed from the target object.