To add a custom page in Edumy Premium Moodle LMS Theme:

1. First please enable the “Include a Topic Section” setting for the front-page. (You might not want this showing generally, but you need to enable it temporarily in order to add a custom page).

You can do this at Site administrator > Front page settings > "Include a Topic Section” 

2. Go back to the Moodle front-page, and at the very bottom, you should see a topic section with an “Add an activity/resource” link at the bottom. If you don’t see the “add activity/resource”, then try turning editing on from the front-page, or enabling blocks editing from the Moodle admin page.

3. Click “Add an activity/resource” and select “Page”.

4. Then, you can either include the static page content in the main body of the page settings, or alternatively you can just enter a blank line/space here, save the page, and then add some custom blocks to the page instead. This is how we do it in the demo, using the custom blocks that we have developed. So after the page is saved, we’ll select “Add a block” from the user navigation menu, and then set this to the “Fullwidth Top” region, or “Above/Below Content” region, depending on where we want it to show on the page. "Fullwidth top” region will spread the block across the entire page (ignoring any maximum widths in the main body container), and “Above/Below Content” region will box the content into a regular main-content-sized container. And then you can use the Sidebar regions too if you wanted to add another block to the right sidebar for instance.
 

After the page is added, you can add it to the main nav menu by going to Site admin > Appearance > Theme Settings > Custom menu items, and paste the URL to the page as a new menu item.