This page consists of screenshots from the Overlays – Manage Overlays Screen in Google Maps Bank WordPress Plugin.
This gives an idea about how to Manage Overlays.
Manage Overlays page allows you to manage the existing overlays. You can edit the settings for existing overlays or delete them if required.
Once you would reach the Manage Overlays page, you would be able to manage different overlays for the selected map. For this, you would need to click on particular tabs which you would like to modify from top of the page.
You can delete multiple overlays together by using Bulk Delete option or you can delete them individually by clicking on delete icon from the Action column.