It is really simple to add a category through your admin portal! Here is a step-by-step guide:
1. Go to https://yourmarketplacename.arcadier.io/admin
2. Log in using your credentials
3. Click on "Content Mgmt.", then "Categories"
4. Click “Add a Category”
5. Insert the name and image of your new category.
6. Click “Save” and.. Voila!
Additionally, you may change the order of how categories are shown on the marketplace. Just click the hamburger icon () of the selected category and drag it to your desired position.