lock for sliding door, part 82-315

I was recommended from a previous post to acquire Swisco part 82-315 for a lock on a sliding door. The problem is that it has a piece to insert that exceeds the diameter of the hole in the door. There are two spaces that would have to be enlarged, and I'm not sure I can do this. Shall I get a refund by returning the part I bought, or shall I get advice how to mess around with tools to try to make this one work? I am not a good handyman.