"Those people are waiting for their families now."
Translation:Ti lidé teď čekají na své rodiny.
Why can't i put teď at the end?
Like, let's say a group of teenagers went shopping and now they are standing around, waiting for their families to pick them up (maybe for some family plans, like dinner or visiting grandma)
The point is not what situation there is out there but what is the information you want to say.
If there are people and you want to say that they are now waiting for their families, then use wording above.
If you want to say that they are waiting NOW and not at some other time, as someone perhaps suggested, then you can use your wording.
It is all about the topic and the comment
I will add your wording, but please understand they are NOT at all equivalent. The meaning often changes with word order changes in Czech. The problem with accepting these is that it leads people to believing that it does not matter what you put at the end of the sentence. But it matters a lot.