I would like to trim the walls as shown in the picture. I can't trim them to the roof as they go further up than the roof. Hope someone can help me to the right, and hopefully easy method. I am new to Archicad, but have experience from Revit.

Hi! I am a beginner in Archicad, but not to BIM. I have created a new wall by changing an exsisting one under Options, Element Attributes, Composites. All well so far  But how do I add this wall to favorites so I can start using the wall?