Hi and welcome to the forum 
!
If I understand you correctly, you want to add this data programmatically.
What you are showing here, is the format in which a Structure field saves it data.
That data is yaml encoded, and can be updated like in this example: CSV to Structure Field - #3 by texnixe
So basically, you fetch the existing data into an array, add the new data, and save the encoded data to the page.