How to pass a [0] value from a List to another script?

This probably sound so easy, but I don’t have a clue.
Is there anybody with at least a small hint?

Here’s the code:

public List<Transform> targets;
public Transform selectedTarget;

private void SelectTarget()
	{
		targets [0] = selectedTarget;
		playerMovement.AutoTarget ();
	}

The Transform which is in [0] needs to go to playerMovement.AutoTarget ();
In that script I want to use this transform/object to point/target/look at.

I tried various values in between the (), but nothing which I tried works…

playerMovement.AutoTarget(); should have a parameter

public void AutoTarget(Transfrom target)
{ }

And than you can pass value playerMovement.AutoTarget(targets[0]);

You should read about methods in C#, if I understand your question right.