To add specific content below the products grid on a specefic collection page :
1- On template editor find “Sections”
2- Click on “Add a new section” and a name to the section you want to beshown below grid
3- Enter what ever you desire, like simple HTML, in new created section
4- Save the new section and find “collection.liquid” in “Templates”
5- Add following condition to the end of the file :
Copy to Clipboard
6- Save and go! 😉
Note: If you want to call snippet in a section then :
Copy to Clipboard