How do I teach someome play guitar?

[Linnil]

I've been asked to teach my cousin play guitar. It's a one time thing. He has never played before. I figured I could teach him two chord shapes and the pentatonic, but after that I get lost. He probably is going to want to see an example or play a song, my mind will go blanc.

What should I show him as an introduction to guitar? All advice is welcome

 

[Linnil]

The C chord is important I'm not sure why
Keyboards start on C, not sure how it's relevant but yeah
a formula is C-E-G?
i don't have my glasses on and i'm stepping out

Because you’re usually taught in C major at first. It has no sharps or flats

 

[Ryan Vega]

Just show your cousin smoke on the water and watch him evolve