In this how-to guide, we will be going over how to build pages in Site Designer using blocks.
Navigate to Site Designer. If you are not already editing your live theme, click the edit (or continue editing) button to open your theme.
Look for the page selector dropdown. By default, you should be editing your home page, and the dropdown button will display "Page: Home." Click the dropdown button and select Master Template from the available options.
You should now be viewing the Master Template. This should be evident by the page selector dropdown displaying "Page: Master Template," and a Page Content placeholder area displaying in the body of your page.
The Master Template has two sections where you can add blocks: the top of the page, and the bottom of the page. Hover your mouse over one of the existing blocks in one of these sections to reveal the plus icon button.
To add the block:
Now that you have added the block, you should see it displayed on the Master Template page. Navigate to other places to see that the block is now on all your site pages: