Did you look at the video on it's ExtensionStore page?
https://sketchucation.com/plugin/1103-extrudetools
I still don't have time to do a video on the entire process but maybe this will help. I copied out the needed edges from the L I already made for this. Note that the straigh edges at the ends need to be divided into multiple segments and welded to make them curves. Two segments is enough, though. Going through the options I chose to no delete the original curves. Since the entire letter gets done in stages, you can't delete all of the edges after an extrusion because you'll need them for the neighboring steps.
[image: 1751719413407-eebyr.gif]