Here's how to do it:
1. Nod your head: A clear and decisive nod, similar to how you'd nod to someone in a conversation.
2. Tap your chin: Use your index finger to tap your chin lightly, almost like you're saying "mm-hmm" verbally.
Important note: The "yes" sign is a combination of the nod and the chin tap. Doing only one of these is not enough to convey "yes."