How do rotations work?

I know this might be a little broad, or sort of obvious I guess. But I’m having trouble wrapping my head around how things rotate in Unity, specifically if you want to rotate something towards a specific point. Could anyone give me sort of a simplified explanation or an example?

this is technically 2 separate questions, but I can see how they go together.

first rotations in Unity are based on quaternions (if this term sounds like it is coming out of an alien language don’t worry you rarely have to do work directly with them), but most of the time if you want to do rotations your going to be working with Euler angles (rotation of angle about axis).

the best reference for understanding how to talk to them is here, but the gist is that your going to be doing stuff like

transform.Rotate(angleX, angleY, angleZ);

for the second part of your question I am going to presume that your talking about rotating to face target. which can be done with Slerp (its just an interpolation, and an example is given in the reference)