how to populate a datagrid

[StefanHoutzager]

Say I have a formdefinition like the one in the attachment. How should a json with a populated grid look with f.e. two rows with data (I will manipulate the json based on database contents on the server)? Can you give an example?
edit_user-formatted.txt
The issue is solved, I customized ngformbuilder for these special needs.