Hi,
If the related products don't show, there are two things to check:
- In the HikaShop configuration, you'll find a setting called "Modules under the product page". That setting should have by default a "related products" named module selected in it. If that's not the case, then maybe the module has been unselected from that option, or the module has been removed.
- In the Joomla modules manager, you need to check the settings of the "related products" module which is selected in that "Modules under the product page" setting. If the module is not there, then you can create it with the "new" button of the modules manager and using the "HikaShop content module" as basis, and in that case, you'll have to reconfigure it to display the related products. You need to check that the module is configured to display all the products of the shop, but with the "synchronize" setting activated and the "relation" setting set to "related products" so that it will filter out the products not related to the current product page.
If you're lost in all the settings there, please provide a screenshot of them and we can tell you what you're missing.