my friend is getting her first guitar in a few weeks and apparently im giving her free guitar lessons, and she knows absolutely nothing about guitars so where do i start and how exactly should i structure the lessons?

i mean should i teach the notes on the fretboard first and then explain how to form chords from that, or teach the major scale? or is that too complicated, should i just start with simple exercises?
Depends on her attention span, and what she wants to learn. Obviously you want to start off with what the strings are and how to tune regardless. If she wants to really study it, I'd tell her to memorize all the notes fifth fret and below, and then give her a chord and scale chart for C major. Not an actual figering diagram, but a chart saying, "A C chord is C, E, G", and have her work it out herself for the first couple weeks.

If her attention span isn't great, or if she's looking to play, but not necessarily study, I'd teach her a few basic chords, and then show her a well-known song that uses those chords. If her attention span is lacking, you want to make sure she's seeing quantifiable progress asap..
I would first begin with easy songs like smoke on the water or zombie(The Cranberries) because these songs will teach her a bit how to use her fingers and it has a a high fun factor. Scales etc. are more advanced things. Songs by AC/DC are easy too. I would teach her some finger-practice licks like this:
Up and down picking:
E-5-5----------------------------------------------- and so on

How to build chords is very much theory and boring for a beginner
You should start with things that will achieve her goals on guitar, and make mini goals along the way so she can feel like she's accomplished things.

Ideally, starting should be about posture, basic open chords, notes on the fretboard, switching chords, rhythm (counting beats, metronome, tapping the foot), simple melodies, in that order preferably. When she has that down, what's better than learning her favorite songs. Then when she has some good experience in playing in time, it's probably time to teach her a bit of theory i.e., the major scale, triads and tetrads (chord formation), intervals, and such.
Before you do anything you should explain the parts of a guitar to her. Primarily, explain what frets and the strings are (the frets are the metal bars found on the fretboard, or fingerboard if you will, of a guitar. "Fretting" strings involves pressing down on a string with your finger directly behind the fret of your choosing. This is how we change the pitch of the guitar. The higher you fret the more you are shortening the length of the string, thusly increasing the pitch). Then you can explain notes, then have her play some "Ode to Joy" or a C major scale, and explain (a little bit, not in depth) how you can make a C major chord from that scale. Then teach her an easy song.
Play the music, not the instrument. ~Author Unknown

Who's the band that could become the next led zeppelin?
Iron blimp.
Aluminum helicopter.
*Breaks out periodic table* Magnesium bi-plane.
Hey, I gave my first guitar lesson to a friend yesterday. He wanted to play rock only; and he was into Nirvana. So I started with showing him the pattern for power chords and taught to play the Smells like teen spirit's intro. And just showed him how to tune and also the parts of the guitar. He was smiling all time when playing SLTS. Like that in the first day make them excited and happy, so they'll love learning it. Go for songs she like and teach a simple part of them with what you taught her in the first day.

Next time I'll do the chromatic scale, just to get his fingers ready to play some simple lead. And also how to hold the pick; only down-strums.