Adding 5" extension to 1987 evinrude 40 hp vro

[ShouldHaveBoughtAGun]

I bought someone elses headache of a boat, then the motor died. Spent twice as much getting the motor fixed. Transom is basically powdered wood. Bought brand new carolina skiff 16 dlx, but it has a 20" transom but the motor is 15" shaft. Has anyone had the pleasure of installing an extension kit (514 from bay manufacturing) I'm trying to get a basic know how or links to videos that would help on how to do it before I spend yet another $500 on this paperweight of fishing dream.