There are many ways to initiate an action.
One is to select it from a task drop-down menu (three dots). It’s the quickest way, since you don’t have to open the folder.
The other one is to open the folder and click the corresponding icon near the upper right corner.
Both ways lock the folder for writing. From now on noone else can perform an action on this folder.
The form is displayed with ‘Cancel’ and ‘Confirm’ buttons underneath. If action doesn’t have a form assigned, you just have to confirm your intention.
Cancellation unlocks the folder without saving and causes return to previous view. Confirmation saves provided data and may cause stage change.