VNP
If you need to make changes on multiple products:
STEP #1
goto PRODUCTS module and select the category product you want to modify, then check the box showed in the below image and all products of that category will be selected. If the products are many and are distribuited on more pages, you have to confirm you want to select all products present in all pages
STEP #2
After having selected all products, at the end of the list will be activated the 3 icons "payments", "shipping" and "workstation" and you can operate on them