GameplayAbilities and you

Hey!
First, thank you so much for this post : amazing job!!
I’m having issue with Tag handling.

In a gameplay ability, I understand that if I say “ok, the one triggering this must posses a specific tag,if not, I’ll just don’t do it”
The problem that I’m facing is “How to I set a gameplay tag” on, per say, the BP_Hero in the example from .

To be working, must it implement the interface UGameplayTagAssetInterface ?
I’ve tried, in BP, the “Add Asset Tag” and “Add Granted Tag” but not working.
In dispair, I also tried to add a random GameplayTag variable but of course it didn’t work.

Can you help please?