Creating custom admin pages with WordPress and UiPress is super easy with the release of the admin pages creator in version 2.3.
If pro features are enabled you will a new option in the main menu called 'admin pages'. Click on this and you will see an empty table and an option to create an admin page. These work almost identically as creating a post or a page.
Click add new and build the content you want in your page. For this you can use the block editor, classic editor or a page builder of your choice.
Once you save and publish the page it will be automatically added to the menu.