I replaced mine a couple of years ago. I did pretty much what Angie did, except I used Carpet tape. This was recommended by Amy at APQS. Once I had the old leaders removed and any excess adhesive on the conduit pipe removed, then I placed my double sided carpet tape. I lightly pressed this on the pipe, just in case I need to straighten it out. Once the tape was on, then I lined up the canvas leaders on the carpet tape, just pressing lightly again until the leader on was on the length of the pipe. Then pressed down securely with my hands.
Before you take off your old leaders, make sure you know which way your leaders roll on to the pipes. I marked the end of my pipes with blue painters tape and an arrow.
It really is pretty easy to replace your old leaders, just take your time.