Delete Multiple Selected Submissions at one time

Please explain how can I select a group/multiple of submissions and delete them all at one time and just keep the ones that I want?

You can do a selected selections of each submissions in the form's View Submission page grid.

You can do the pre-selection by holding down the CTRL key + Left-Clicking to select the submission.

This way you will be able to pick/select specific row/submission in the grid that you can now delete selectively.

Check the animated image below for better understanding on how it works.

Hope this help. Please let us know if you are not able to make it work.

By the way, please take note that deleted submissions are permanently gone. 

So you should also make sure you have a copy/backup of them in case you need those submission data later on.

Thanks.