How do I show my best-selling products automatically on the home page?

Use the Source setting in a product section.

1. Open your product section, or click + Add, pick the products category and choose one such as Premium Product Slider.
2. On the Content tab, set Source to Best selling — most units sold.
3. Set Number of products (1 to 50). If you leave it empty, 12 show.
4. Click Save.

The list ranks itself by units sold, so it keeps up as your sales change.

Other sources: New arrivals — newest first, Trending / featured — products flagged Trending (products where you ticked Mark as trending on the product), price low to high or high to low, and Name — A to Z. You can also set Filter By to Categories to show the best sellers from one category.