Hey Maureen,
I believe you already have a row for check boxes in your Activity Grid so we skip that step.
Now add a Button to the screen (e.g. 'Delete Selected'):
- Loop Through Grid (Activity) (NOTE: ONLY CHECKED ROWS is crucial here)
- Now in the loop add a 'Delete Record From Table'
This is my full Action Set:
Maureen remember this action is irreversible, use with caution. I would throw in some Conditional Warnings in the Action Set to be safe.
I hope this answers your question.
- Mortaza