There are two ways to edit a gallery's template. The first is by editing the template on the page. This is useful if you want to see the changes in the context of the page. 
The second way is through the edit template mode where only the item template with it's default content is shown, for if you want to focus on the template's design on its own. 


To edit the template on the page:


1. Select the gallery that you want to work on. 


2. Select an individual item in the gallery.


3. Click the Edit Template button in the Template tab of the main toolbar. 


4. Edit the template as you like and then click apply. Note any changes made to a template will automatically be made to all items using that template. 


To edit the template in Edit Template mode:


1. Select the gallery.


2. Click Edit under the Gallery Item Templates section of the settings panel. 


3. Edit the template as you wish and click Apply. Note that all items using the template will be affected by the changes you make in edit template mode.