Creating categories and move products

In order to see products under specific categories, you need to move them into categories.

Suggest you watch a tutorial on campus about creating categories first. Here is the link https://wholesalerobothub.com/campus/lessons/working-with-categories-and-adding-them-to-the-menu-bar/
After that, you will have to move products into that categories and they will be linked up.

To move products into categories - here is the step-by-step tutorial:
Once you created new categories you are always able to move products one by one or by selecting more of them at once into any category you like. Log into your Admin Dashboard then click on Catalog - Products, there you are able to see all the products which are currently imported. Click on the check box next to the product picture in order to select the wished ones and then under the category column click on any category name for products that are selected. When a new pop box appears change the category to the one you wanted and all selected products will be moved to that new category that you selected. Please take a look at the presented image example: