To add the custom menu to a specific page using Elementor:

1. Create the Menu
   Go to Appearance → Menus in WordPress and create the menu you want to display.

2. Edit the Page with Elementor
   Open the target page using Elementor (make sure the page layout is set to Elementor Canvas if you're building it from scratch).

3. Add a Header Section
   Copy and paste your existing header (or create a new one) into the top of the page using Elementor’s widgets.

4. Insert the Menu
   Drag the Nav Menu widget into the header section, then choose the menu you created from the dropdown under Content → Menu.

5. Style and Save
   Customize the look as needed and click Update to save the changes.

Now the selected menu will appear on that specific page.