Wow, what a wide open topic. I'm going to ramble for a bit.
I suppose you have to start with history fundamentals. Poker came into popularity at the turn of the last century, now we've got 52-cards, and three of a kind beats two pair.
This is how a poker table works. This is a dealer. This is a button. This is what happens when you don't have a dealer. This is how you buy chips. This is how you buy more chips. This is how you get on the board for a table. This is what chips ARE! We used to use white/blue/red bicycle chips, but now we don't and here's why. This is how you leave a table. This is the etiquette for tipping, ordering and eating food, and when you have to call the floor person.
And then, you teach an abridged version of the Hellmuth book. Hand values, absolute position, relative position, outs and direct odds, implied odds, managing pot sizes, ranges, tells, and the Tao of Poker.
If I had 2-3 hours, I'd start writing my syllabus.
I envy you.