How to submit multiple rows of a table with checkboxes

I want to submit multiple rows from a table to a server-side action. This should be done by checking the checkboxes of the rows that needs to be submitted, and then the user should press a “submit” button.

This is what I want to pass to server-side:

Knipsel.JPG1776×962 195 KB

I have already looked at the forum posts about this, but I’m not getting correct results and not sure why.

I’m also using a nested structure to submit the form, as mentioned in this topic.

This is what I have server-side:

And these are the checkbox settings:

A live version of what I’ve made so far can be seen here, just in case that helps. Hope that someone can explain me step by step what I should do.