i'd go:
1. Grip
2. Groundstrokes from the back (because it includes defending) and how to pivot. rotate body, open racket short, hit with body rotation in front of you. use 2nd hand to show where you wanna hit it and to activate the shoulder rotation. This alone is a) easy to do, b) fun to do c) brings you into a rythm. just play back to back of the court, correct her movement just a bit but let her focus on hitting the shot and getting a feeling for the pace etc.
3. Volley. if possible same: pivot, use 2nd hand to point to the impact point. get back to neutral. here the same, let her get into a rythm, maybe first with forehand (easier to volley), then backhand (probably way more corrections, shot feels not natural, not good for only 1 session)
4. defend after the glas, parallel. no angles (cross), just like 2. but with longer shots from you so she can pivot, open the racket, wait for the ball to pass and hit it when it goes forward.
5. lob! dont forget how important it is to transition. Let her play 2x low, 1x high. all easy shots so she feels what to change. preparation should be the same but open the racket and go up with the full body.
this is more than enough for the first session and should give her a good idea on pace of the ball, how to hit without a weird, mechanically tricky technique and get an idea about rythm, moving before, with and after the shots.
in the next sessions you can do cross shots (how to position, where/when to hit, reading angles) and maybe start with a first easy overhead (bandeja).