The checkbox I was talking about was the fact that your drumset should be used in the project. If you want your drumset to be used with your song, you should generally select it as a Default Drum Set. You’d better do it now and set Default Drum Set to be your ‘boom chac’.
I simply named note 24 as ‘24’, and note 28 as ‘28’, that’s why they are repeated twice. This is not an issue at all.
Judging by your screenshots it is totally impossible to play anything with the project you show me.
So you must be using another project to play that file. I’d recommend using that project for adding your new drumset to as well.