I'm stuck at a mission "why not warm up with a quick show before the big..

Hi! When you press any TV on the Sims, it will give you the options of:
- Watch news.
- Watch show. (TV show)
- Watch a Movie.

The "big Event" they are referring to, is a movie. You need to get three Sims (I believe it is three, sorry if I am wrong) to watch the second option: a show. This should take 20 min.
If you are unsure of how to get multiple Sims to watch a show, this is how:
1. Buy a TV, if you don't have one.
2. Check the area is clear in front of your tv. Make sure that you can seat as many as necessary, either on the floor, sofa or chairs. You may need to buy these as well if you don't have them.
3. Select a sim.
4. Press on the tv.
5. Select "watch show."
6. Select another sim.
7. Select "join in."
8. Select another sim.
9. Select "join in."
10. Do the last two tasks as many times as necessary, until you have got the right number of Sims watching a show.

I hope that helped!

Watch tv. Watch a show is one of the options.

This means to buy a tv and then have them watch a show. To have the watch a show, tap on the tv and it will give you a few choices.