Steps:
Theme editor (Customize) > Add Section
Search Portfolio
Click Save
You can add blog tab with Tab item blocks.

You can enter the Heading and Subheading, choose the design for the heading, also can choose text align: center.

With these options, you are allowed to set the Portfolio item design, text configurations, images , effects, and colors.
Please follow this guideline to config Layout, Background, Margin/Padding for the section.