The collection template can include optional blocks. These blocks are displayed in-grid alongside your products. This can be used to display a text block or a newsletter. Both of which are great for highlighting ongoing promotions

Go to Online Store > Themes > Customize
From the dropdown in the center of the top bar select Collections > Default collection
Select Collection grid from the theme sections
Click Add Block then select either Newsletter or Content.
Click into the newly created block
For the Index field enter the number position you want to display within the collection grid.
Update the content of your block as needed
Hit Save
Start by connecting your source repository and choosing the pages you want to publish.
You can then browse your documentation and ask questions about the content your team has shared.