Hi Jonathan,
For this, you will want to use either the Less than or Less than or equal to filter. Your choice will depend on if you want to include customers whose last activity date is exactly 30 days ago.
In order to use this filter, you will first need to calculate the current date minus 30 days and store this value in a shared result to use it in your filter. I recommend doing this in the OnScreenLoad actions.
Your actions will include:
1) Assign Value to Action Result – To retrieve the current date
2) Date Add – To subtract 30 (or add “-30”) days from your action result
3) Assign Value to Shared Result – To copy the calculated value from #2 into a shared result for use with your filter
3) Enter Value into Field On Screen – To copy the calculated value from #2 into a date picker object for use with your filter
Give this a shot and let me know if you have any questions. I hope this helps.
-Audisho