How to Add Multiple Products to Product Category:
1) Under "Product" Menu on the left hand side of the Builder
2) Select "Products"
3) Click on the Drop Down arrow next to "All Categories"
4) Right Click on the Category you wish to add products to
5) Select "Edit Category"
6) Click on the "+" button at the bottom of the Builder
7) Here you can search products by Name or SKU, when finished click "Select"
*To select multiple products at a time, Hold down "CRTL" on your keyboard while selecting*
Make sure to Publish after changes are complete.