The row selection component lets you select which rows will be processed.
TIP: if you are not sure which rows will be processed click the eye icon. Add-on displays the start row and how many rows will be processed for the option you selected.
This video is for another add-on AnyMerge Docs but the principle is the same. Please note AnyMerge Mail add-on does not have the option to process rows from last processed row (option two in the video).
Add-on processes all data rows in the source sheet starting on row 2.
Add-on processes only selected rows. Hold the Ctrl button and click on row numbers in the source sheet to select one or more rows. Or hold the Shift button and select a range of rows you want to process. This option is super-handy for reprocessing when you made some adjustments in data and you would like to pick only one or few rows to be reprocessed.
From Selected Row
Add-on processes all rows from the selected row down (including the selected row). Hold the Ctrl button and select exactly one row.
Add-on displays the start row number and how many rows will be processed. Add-on guides you in the selection process and might return some warnings when you make an invalid selection like incorrectly selected rows. Once the add-on stops complaining you are ready to go.