When I use behavior tree ,I found confuse about the Cooldown,Tag Cooldown and Set Tag Cooldown.
In the Tag Cooldown and Set Cooldown Decorator, there is a Cooldown Tag , I have no idea to set it.
I am sorry for my poor English.
I used the following to setup mine: How do I use the FGameplayTagContainer and Tag Editor? - Programming & Scripting - Unreal Engine Forums
As Dave Ratti says you need to set [GameplayTags] ImportTagsFromConfig=true in your DefaultEngine.ini and then you can add gameplay tags in the editor by Edit → Project Settings → GameplayTags. After setting ImportTagsFromConfig=true it shows up right underneath description as the second item in the list.