Do you need to add new tags and associate them to your products?
Here's our 3 step process:
1. Filter products you need to add the new tags onto
2. Select the filtered products
3. Add and save the new tags in the 'Tags' panel in the property column
That's done! Tags are created and associated to the filtered and selected products.
Note that ticking or unticking the select box will associate or dissociate tags to selected products in bulk.
Tick or untick, your choice :)