Reservations Forms in Gourmet theme are managed via separated plugin Open Table Widget which is available for free here.
We highly recommend you to read official plugin documentation to get detailed information about Open Table Widget plugin.
After plugin installation is available new Widget in default WordPress Appearance > Widgets options. You can drag and drop Open Table Widget into prepared Widget Area to display Open Table Widget in sidebar anywhere on your site.
To display Open Table Widget inside content of any page we prepared in Page Builder the Widget Area Element which allows you display selected area inside place of page content.