Login to your website and then visit the front end as if you are a visitor.
Find the page whose gallery you wish to edit.
Click on “Page Builder” – see screenshot: 
Click on the pictures.
This will bring up a pop up – you will see a link “Edit Gallery” – click on this link
You can delete any of the photos you don’t want and drag and drop into position the photos to put them into the order you wish them to appear.
To add photos click on “Add to Gallery” – see screenshot: 
Either add existing photos from the gallery, or use the Upload File tab to upload photos saved on your pc.
Once added, click on the blue “Add to Gallery” button – see screenshot: 
Then click on the blue “Save” button on the pop up – see screenshot: 
Then click “Done” top right hand side of screen – see screenshot: 
Then click on “Publish Changes” – and that’s it!