Step1: Get into the Builder. A toolbar will appear at the left corner of your page, 3rd tool of this toolbar reads 'Heading'.
Step2: Click on the block to which you want to insert the Heading and then select the 'Heading' tool.
Step3: TO RESIZE YOUR HEADING:
1. Click on the heading and a toolbar will appear on the right side of your screen.
2. Click on the second tool of this toolbar reading 'HEADINGS TEXT'.
3. Chose the Heading size of your choice.