Click on the Edit link in the Product Detail Display area at the top of the page.
On the Product Detail Display Options page, enable Cross-Sell by selecting Display, and configure cross-sell display settings.
Click the Download button to download and save the product detail page cross-sell code text file. The download button for the code and instructions are located near the lower-right of the screen, below the Cross-Sell preview module.
Click the Update button to save your cross-sell display settings.