Run the script
In the WSL terminal, type: ./runVar2Compform.sh (or ./runVar2Compform-BB.sh or whatever you have adjusted the filename to)
That will:
adjust the first two variables in PromoteSubentries.ini, for your FLEx project name
run the Var2Compform.pl script, which will do the following:
extract the .fwdata file from the backup
convert variants marked with your special tag into complex forms with the same Complex Form Type as your Model Subentry
put the .fwdata file back into the (same) backup file
It also leaves the intermediate .fwdata files in this folder; you don't need to do anything with those, and you will want to delete them once you are sure things worked correctly.
In FLEx, restore from the resulting backup (let it overwrite your other project, assuming you kept a copy of the original version of the backup somewhere else).
Verify that you have subentries of senses, with the correct Complex Form Types.
Make a backup, with "Changed Variants to Subentries" in the comment (or something similar).
Proceed to format your “subentries of senses” however you need to format them. You will likely want to make Senses and Subsenses “Display in paragraph”, as well as: Subentries, subentries of senses, and possibly subentries of subsenses. And you may need to create separate styles for each of these, so you can set the indentation separately for each.