You can get complicated with setting a compound miter on every cut, or you can cut in a jig, upside down and backward. Unfortunately, a good video has gone subscription only, but by carefully examining the photo and reading the text, you might be able to figure out the technique. The author also suggests making to sample boards, One each Left-Outside, Right-Outside, Left-inside, Right-inside. Label them and use to verify your set up before you turn on the saw.

Pretend the fence on your saw is the wall and the table on your saw is the ceiling.

Here is a link that might be useful: Upside down crown.