How to setup top 10 automated Bestsellers Collections
Open the search configuration.
Click Add Group button, to add a new collection group/choose existing collection group.
Click Add Collection button to add the collection pages.
Click Edit Merchandising button to update merchandising on the collection pages.
Click on Add Rules/Edit Rules, to create a new rules/edit existing rules.
Click on Edit Rules ->Automated Collection tab. Enter the number if products you want to display in the collection. Click on the toggle button to activate the automated collections.
Click on Add Sorting/Edit Sorting, to create a new sorting/edit existing sorting.
In the Best Matches tab, click on Add Best Matches, and select Best Sellers.