Hi @Craig_PaxsonTN,
You can use a relationship column in the child table pointing to the parent row.
This can be set when the child row is created using AddRow.
Example:
AddRow( child table, relationship column, thisRow )
Where it is thisRow, it is referring to the Parent row from which you pressed the button and therefore making the relationship between the two.
This is similar to another forum post I helped with. Please view it here for a practical example: Create a row and reference it at the same button press - #2 by Dale_Cowling
I hope that this helps.
All the best.
Dale