Go to Pages -> Add New, choose a title for your home page, click on COMPOSER button, choose BUILDER template and save page. We COME BACK on this page after create other page section.
CHOOSE HOME PAGE
Go to Settings -> Reading and from Front Page Displays choose a Static Page (your home page already created). Click on Save Changes button.
Go to Pages -> Add New and click on COMPOSER button. Choose template page (Parallax for example), choose a title for your page, fill the fields and publish your page.
You can do this for all your section page.
COMPLETE YOUR HOME PAGE
Complete your home page with your new sections. Re-open your home page, click on +Add and add section to your home page. Click on Update to save your changes. After this, you can change the order of your section with drag and drop function.
CREATE A COMPLEX PAGE FOR MULTIPAGE
Go to Pages -> Add New, choose a title for your internal page (ABOUT US for example), click on COMPOSER button, choose BUILDER template and save page.
Now close this page and create all pages/sections you want to insert inside this page.
Come back to your page (ABOUT US) and complete this page with all section you want to create a complete internal page.