A short movie says more than a picture says more than words...

Tagging animated GIF

Tagging in short

Check 'Maintenance mode?' in the Options section on the right side 'Options Panel'
to avoid auto-closing of the 'Preset Picker' window on preset selection when clicking on a preset in the middle 'Presets Panel'.
Then:
Select one or more presets in the 'Presets Panel'.
You can use 'Ctrl' and 'Shift' the same way as you would do selection in e.g. the Windows explorer.
And then:
Drag the preset selection either over a 'Tag', a 'Rating' or an 'Author' on the left side 'Filter Panel'.
And drop it there.
Tagging done!

Removing tags

This cannot be done with some drag'n'drop mechanism, but instead must be done by using the right click context menu on presets in the middle 'Presets Panel'.
Again you should be in 'Maintenance mode'.
Check 'Maintenance mode?' in the Options section on the right side 'Options Panel'
to avoid auto-closing of the 'Preset Picker' window on preset selection when clicking on a preset in the middle 'Presets Panel'.
Then:
Select one or more presets in the 'Presets Panel'.
You can use 'Ctrl' and 'Shift' the same way as you would do selection in e.g. the Windows explorer.
And then:
Right click to open the preset's context menu and first move down to either 'Rating', 'Author' or to any available 'Tag group'
like 'Category', 'Expression' or 'Genre'.
For 'Rating' there are no 'Add' or 'Remove' sub menues, but instead you can just set the desired rating for the selected presets.
The number in round bracket to the right of each rating expresses to how many of the selected presets the new rating would get applied to.
E.g. if you have 9 presets selected and that number is '(4)' for the 3 stars (yellow) rating, this would mean,
that 5 of the selected presets already have this 3 stars rating and therefore only for 4 presets that 3 stars rating would be newly applied.
For 'Author' or any 'Tag group' this is different:
If the sub-menu which opens to the right of the menu entry where you are just over with the mouse offers a 'Remove' entry
then this means that at least for one of the selected presets an author or tag assignement can be removed.
The number in round bracket to the right expresses the same as it does for 'Rating'.