(M&M 3e) "Harvesting" Characters from Stock

[MPHopcroft]

I got my hands on a stock file with a lot of character sheets in it (long story), which I am researching to see how I can model new characters from. Basically, they would be starting points I would customize from.

This is clearly the sort of thing HL Classic is intended to do, and so far I've been lucky enough not to overwrite any of the stock characters in the file. I'm just trying to figure out how to extract the character from the stock portfolio into a new one where I can change things at will. I've done it before, but I'm not sure how I did.

It's been a while, but it so happens that I need to write in that system for a current project. Where in the online docs can I look for a solution?