There are previous topics related to this that you can review before creating a new post:
https://forum.convai.com/t/ue5-adding-npc-interactable-objects-dynamically/3201/2
As for the NavMesh bound, this is related to your Unreal Engine level setup. Convai only returns the Action. For the character to move, the NavMesh must be correctly configured in your level. I recommend checking the Unreal Engine forums for detailed setup guidance.