Login to Parish website dashboard.
Navigate to Appearance > Menu.
Select the menu that you want to add the new Page to.
Top menu is the menu appearing on top of the website, and bottom menu are the links appearing at the bottom of the website.
Top menu:

Bottom menu:

To add a new Page as a menu item, tick the checkboxes in the Pages panel, next to each of the Pages that you’d like to add.
You can select one Page at a time or multiple.
After selecting your Pages, click the Add to Menu button.

The new menu items will append to the bottom of the current list of menu items. You can drag and drop to re-arrange them.

To create a sub menu, drag an item below the parent item, and then drag it slightly to the right. Example of ‘My Parish’ dropdown in the menu:

The menu item name will default to the Page name.
To change this, simply click on the down arrow next to the menu item name to view the options panel and then update the Navigation Label to your preferred name.
After making your updates, click the Save Menu button at the top or bottom of the screen.