Navigate to SC Options > Demo Importer and click on the Import Demo button. Wait for the process to finish and don't reload or leave the page. Once all the demo content is installed, the page will get automatically refresh and the button will say "Demo Imported".
Process of installing demo content
Adding the button to the Navigation Menu
The last step of the demo importing process is assigning the button to the Navigation Menu. You have to manually select the option to make the Book Online link look like a button as shown in the actual demo website.
Default Book Online link after demo import
Navigate to Appearance > Menus.
Select the Secondary Menu.
Click on the Drop-Down Icon next to the Menu Item.
Change the Menu Item Style to Simple Button.
Click on the Save Menu button.
Transforming the link into the Button
Once the Menu is saved, you can see a CTA Button inside your Header navigation as shown in the image.