How do I preserve the initial rotation of a rotating object?

Hello ,
I’m in a process of creating a scene with few cradles and rocking chairs but their initial rotation will be different in each instance (yet their max and min swing will be preserved and identical)
The blueprint I’ve created gives the desired swing but every cradle and rocking chair has it’s initial rotation reset to 0, 0, 0 each time the blueprint starts.
How can I preserve the rotation of an object and start the new “rotation change timeline” that threats a rotation of an object set on the scene as initial ?

This is a blueprint I’ve created :

you should watch this video, in this video he stores the initial location of the door. which I think is what you’re after.

Thank you for the answer.
I made my blueprint based on exact same tutorial but in my case I need to be able to replicate the behaviour of rocking hair as many times as many objects I put on the scene. Thus I decided to create blueprint based on object instead of using Level Blueprint.
I do also store an initial rotation in a variable using Get World Rotation so everytime the object blueprint is used I can rotate it in desired way and add my swing from Timeline to unique rotation.
Where do I make a mistake or bad assumptions ?