How do I apply a mask?

Edit the template by selecting the Edit icon at the bottom-right of the thumbnail illustration
1.
Edit the template by selecting the Edit icon at the bottom-right of the thumbnail
Select the zone to add the mask to illustration
2.
Select the zone to add the mask to
Select the mask icon from the toolbar illustration
3.
Select the mask icon from the toolbar
Select the mask and select save illustration
4.
Select the mask and select save