Concatenate multiple collection variables once extracted from multi-line text field

Thank you to this discussion, I have been able to extract the comments from a multi-line text field where append text was enabled; however, I am still unable to display the data onto a sharepoint list column:  Solved: Extracting Data from Appended Multi-Line Text Fiel... - Nintex Community

I am using on-prem Nintex Workflow/Sharepoint 2019 and request assistance on this final step in building a string that captures each extraction after using the "Call Web Service" and "Query XML" action resulting in e.g., 4 different data sets, how do I build a string for each data set to display Date, Name, Comment in a new column.

I tried using the For Each and adding a math operation, but it did not work. If you are able to provide examples with screen prints, I would greatly appreciate it.