Hi @Luat
We're glad you're here. When you get a chance, please introduce yourself on this forum thread. I'd also encourage you to add a real picture as your avatar because it helps build community!
You need to use the indexed-repeat
function to get values from another repeat group. You can read more about it here https://docs.getodk.org/form-repeats/
Generally it would look like: TEST.xls (11 KB)
I removed a lot to make that for a clear sample but what I changed is in yellow.