Firstly, thanks for trying out MasterPlan, I appreciate it!
Secondly, sorry to hear it's not working - I have yet to examine M1 Mac compatibility that closely (as I don't have an M1 Mac to test on), though someone else with an M1 Mac experienced the same problem, I believe. There should be no extra requirements when compared to vanilla Macs, so I'm guessing Rosetta isn't currently working with MasterPlan (though I have a suspicion it's caused by the framework I'm using not having ARM-compatible code equivalents for some parts).
Log files should be generated in the "~/Library/Application Support/MasterPlan" directory - if it's not loading properly due to what I imagine is the problem (the framework not containing code Rosetta can use to make a non-M1 Mac program run), then the log files probably wouldn't be created.