At first I was tempted to turn the edge of the carpet under at the step but I decided to miter the edge backwards onto the side of the step at an angle like I usually do. I did a test piece with a scrap and the carpet direction change isn't very visible at all. It's a bedroom and you don't get a straight-on look at it anyway. I sealed the edges of the cuts with hot glue and use hot glue to form the corner of the miter at the top of the stair edge. With the hot glue softening the carpet backing at that miter point you have a lot of control as it begins to cool and can mold or form it like putty sometimes...... fuzzy putty.That carpeted step is not to shabby for a rookie. Nice job. Hey on the floor that has the copper pipe in it if you turn up the heat and damp mop the floor near the walls it will show you where the pipes are by drying first, just mark them with a marker and you are good to go. I hit 1 water line and 1 refrigeration line in my years of installing. The refeer line was in a bar. Shut him down for the weekend and was he poed. When they are buried in concrete it is a crap shoot.
I actually pondered hand sewing that corner, but folding it back to sew it would have been a pain in the ass.