If you want to relate the same product, for example:
Register product A and B, then relate as same product on both pages.
Example: Perfume 30ml is a product and Perfume 50ml is another product
01) Access the Control Panel
02) After login click on Catalog >> Select the category or subcategory >> Select the product
03) Click the SAME RELATED PRODUCT button
04) In column A is the product selected and in column B is another product that you want to relate
05) After clicking the RECIPROCATE button (to stay on both related pages)
