How to Create Product Variations using Bulk Variations Manager

 
Step 1 – Select the ‘Create / update variations in product/s’ option.

Step 2 – Select ‘Use all products from selected categories as base products’ from the available options.
And then set a base price.

Step 3 – Choose attributes & its values from the provided checkbox. Add differential price (optional) to set-up variations.

Click Apply.

Your variations are ready.