I just watched a part of that tutorial you posted, where he explained how to rotate the head bone. Which you want.
You just need get to location of the object where want him to look at and find the look at rotation for that, in pretty much the same way you have in the 2nd screenshot of “turn_head_graph”.
Try to break down what your goal is instead of looking for a copy-paste answer.
You want:
Rotate Head Bone.
Get vector location of the object you want the character to look at.
Set the look at rotation of the Head Bone somewhere in your Animation BP.
Have some rule to decide when to look at a object and when not.
Set a max rotation so that it wont spin around 360 degrees.