The holes in the bottom are to let out the dust while you are tapering the shafts.
I chuck the shaft is an electric drill and work it back and forth slowly until it hits the stop.
You can size shoots with it but if they are thick you have to go slow.
I used small sanding belt(120 I think)and cut strips to fit and attach with double sided carpet tape.
I don't have pics of me working with the jig.