I'm also struggling with this. I could very well be wrong but this is my understanding on how it's done:
I believe you want to use the "Rotate towards angle" action.
You need to have a trigger that is constant until your object has reached the desired angle. In other words, this way the action is looping every tick until it you get to the desired angle.
The "Degrees" parameter is how many degrees it'll rotate each tick and the "Angle" parameter is the desired angle.
As a side note you'll probably want to use the delta time expression with the "Degrees" parameter so that the speed isn't linked to the frame rate.
This does seem a bit long winded to me which makes me think I've got it wrong. If anyone has a better method I'd be interested also.