Originally Posted by: pratterrSince music is movable how do you know what key single note patterns are in?[/quote]

The key signature is determined by the closest matching scale used by all or most of the notes of the riff or melody.

Originally Posted by: pratterrSay I'm playing twinkle twinkle little star and the first note is open E. Does that mean it's in the key of E?[/quote]

Yes, but that just because the melody of that tune happens to start on the root note of the E major scale.

To pick another example, Mary Had A Little Lamb starts on the major 3rd scale degree. So, if you start that tune on the note E, then you are in the key of C major. You can determine this by considering all the notes of the melody.

e-d-c-d-e-e-e

d-d-d

e-g-g

e-d-c-d-e-e-e

d-d-e-d-c

You can determine key signature more often by the last note than the first. But even that is not a guarantee. The best method is to consider all the notes as a system.

[quote=pratterr]And if I move the pattern up a half step would it be in F then a whole step to G?

Yes.

[quote=pratterr]I don't know what notes to use with do different keys.

Then all the notes move relative to the root note. This is why it's a great idea to learn scale patterns as numbered degrees.

C major scale for beginners

https://www.guitartricks.com/tutorial.php?input=363

A minor scale for beginners

https://www.guitartricks.com/tutorial.php?input=445

And this tutorial on ear training for intervals is a good way to understand why knowing scale degrees is a valuable skill.

https://www.guitartricks.com/tutorial.php?input=2401

Hope this helps! Please ask more if necessary & best of success!