Trying to set and save multiple Check-Marks in repeater

Hello ladies and gents,

I´m a little novice with repeaters and wix-code and really hope to get some help with my issue.

I have set up a repeater which is Connected to a Dataset. “dataset1“
each „item“ has some textfields and also one Check—Mark (Type: boolean).
In Addition there is a submit-Button.

my goal where I fail:
If I Click on some of the Check Marks (multiple items), to set the boolean-field on true, and submit afterwards it only „Saves“ the one on top of the list in my Database, but not all the other selected ones.

Anyone here who can help me?