How to enable or disable the Coming Soon / Maintenance mode pages
You can easily enable or disable the Coming Soon / Maintenance mode page in Customize > Homepage Settings > Maintenance mode page. Simply select the maintenance page and it will be visible to your customers. Don't forget to publish your changes.
You can edit the maintenance page in Dashboard > Pages using the VamTam Beaver Builder

How to disable the Coming Soon / Maintenance mode pages
You can easily disable the Coming Soon / Maintenance mode page in Customize > Homepage Settings > Maintenance mode page. Simply leave the option unselected. Don't forget to publish your changes.

How to edit the Coming Soon / Maintenance mode pages
In order to edit the background and content of the Coming Soon page, please go to Dashboard > Pages > locate the page and click on VamTam Builder link:

Usually, the page's background image can be edited in the main Row's settings:

Troubleshooting:
In case you aren't able to access the row's options bar:

please add an empty row above:

And you'll be able to access the row's options bar. Next, please remove the excess row:

Please check this guide for more details: Guide to Vamtam Beaver Builder