Cannot find the right set node

I’m pretty new to UE4 and especially blueprints (usually I work with unity).
I started following this tutorial to create a first and third person camera with blueprints and up to this point everything worked fine.

I created the timeline but I cannot find the right set node.

This is what I have right now:

and this is what I want to have:

Only thing I found that looked somewhat close was when I clicked on Target Arm Length and made a variable out of it and then drag the variable on the screen and selected set. But there was still the target missing…

Link to the tutorial: Add first-person arms--Making a character Part 3--Deplorable Mountaineer

It is a variable of the “spring arm” component (aka the camera boom). Drag a wire off the camera boom reference and search for “target arm length” it will show up.