I cut the blank, scribe my borders and do the gouge line if I am using one. Tape the back of it like I normally would and do my tooling.
Then I do my dying, and whatever else I will do to color it.
Glue and stitch the liner and punch my holes then edge the entire thing.
Then I apply my finishes or sealers.
I guess you could sew in the liner first before tooling but knowing my luck I would either screw up the liner and or mess up on the tooling and have to start over. I dont have a sewing machine so sewing a belt is a little bit of a chore so I wanna know for sure the belt is good to go before I start stitching.