https://youtube.com/shorts/HPKr5F9mnxM?si=L1sSoamE1D5knDxZ.  Cut irregular  shape beam

https://youtube.com/shorts/XqLxr557gcA?si=EzNsAHtmPR5OI4zR. Cut 45 degreeish angle  outer corner

https://youtube.com/shorts/HZdINy4li1A?si=TM8fHxda0ZSzV4Zh, Cope instead of miter moulding