As long as it’s on an angle back towards the handle, it’ll cut when you pull it back. Doesn’t need to be overly sharp either. Don’t forget to grind the tip down.
I put a cut with a hacksaw on the end wide enough for the blade to fit into (this helps position it). Drill the hole for a bolt with a locknut to secure to the pole( the paring blade already had a hole in it). The screw at the back is to help keep it at the angle.