Control hand with Arduino in level blueprint

Hi, I’m very very new to unreal engine (using version 4.26). I’m working on a project to read data from arduino (through UE4Duino) as input for controlling hand motion in unreal engine. The arduino variable is stored in the level blueprint.

I only need to change the hand pose to simply open and closed. I’m using the right hand animation from the VirtualReality package, and followed this tutorial from Johnathon’s tutorial. However, I have problem passing the arduino variable into the blueprint under the virtualReality > Mannequin > Animation > RightHand_AnimBP. May I know how to do so?