How to convert es to note

First of all, stop pulling your hair out. MuseScore is actually quite user friendly when you cooperate with it.

What you are saying you are doing makes no sense. What language are you most comfortable with. If it's English then I suggest that you watch a couple of videos that familiarize you with MuseScore or read the manual.

Videos: https://musescore.org/en/tutorials

Manual: https://musescore.org/en/handbook (there's a PDF download link in the top right corner)

I'm not sure what you mean by "es" - I guess this is a mis-translation from some other language but it isn't clear exactly what. Maybe you mean rests? MuseScore does try to keep each measure with the proper number of beats, so if you add a note, the rest that was already there is shorted by the corresponding amount, naturally. Nothing else should be modified, so all should be fine - just keep adding notes. No idea what you mean about dragging beams - that should not be something you want to do. Nor do I know what you want to convert to a note - a rest? You don't "convert* things to notes, you simply enter the notes and they replace the rests or other notes that were there before.

Click below for my Quick Answer on how to enter notes:

Enter Notes

https://masteringmusescore.com/quick-answers/enter-notes