The process of installing a new comb is straightforward.
Here are written instructions on how to install my Dark Combs. (click here for the PDF file)
My combs maximize surface contact and do not incorporate room for the tips of the rivets that stick out on the under side of the reed plate. You need to flat sand the draw plate to install my combs. Flat sanding the draw plate is easy and it provides an additional boost to the performance of any diatonic harmonica. Try it on a harp with its stock comb and see.
Here is the process of flat sanding:
Here's a video of the whole procedure: