Hello,
The easiest way I believe is the following:
1. Add a field to your entity the update of which will trigger your Power Automate Flow.
2. Create a Power Automate Flow with an "On Record Updated" trigger with the filter on the field you created in step 1 and implement the required logic.
3. Check the following video that describes on how to update the current record using PowerFX - www.youtube.com/watch
