(from an ex taekwondo instructor... now practicing karate only)
Taekwondo was spread very fast and wide with little "quality control", so what gets taught in different dojos can be very varied. I'm sure the first thing some WTF dojos would do is get them turning/roundhouse kicks on those little flappy pad things, but I'll just offer what we used to teach at my old school, which was more in keeping with the karate origins of taekwondo....
We started teaching students a "walking" stance - getting comfortable stepping forwards, turning. Then we'd add a simple punch as they step, a low block with outer forearm, an inward block with outer forearm, a rising block (coming up to protect the head from a downward hammerfist or similar), an outer-forearm outward block, and an inner forearm outward block (which will feel pretty weird to new students). By adding a front kick, they can start simple three step sparring - one moving forward repeating either the punch or the kick three times while the other retreats and blocks, then reverse. You can introduce the concept of closing the opponent by blocking their attacking limb across their body, making it harder for the attack to be continued with a reverse punch. The next thing to introduce would be a back aka L stance - still running through the same set of techniques.
We normally wouldn't explicitly introduce the concepts of hip rotation and power generation for the first six months to a year - they'll pick some of that up by watching seniors and their instructor, but it will confuse (and possibly discourage) the ones who aren't comfortable with the basic gross movements.
Another technique they'll probably enjoy is the good old chop - outward knifehand strike. Inward palm block is another technique introduced early - can be good to keep things civilised if the forearms are being used to inflict pain ;-~.
IMHO - too early for side kick, back kick, turning/roundhouse kick. Crescent/slapping kicks can be introduced if they're doing well - for a beginner, just lifting a straight leg up and across the body from outside to in or vice versa respectively - they're good for learning balance, improving flexibility and a little variety more than practical fighting, but get students visualising openings from the sides and hopefully thinking about exploiting them. (Later on with good technique and knee flex they become viable offensive weapons too).
If you throw in the first kata - that should be enough for a couple months, mixed in with some stretching, strengthening and general fitness exercises.