see in the first sentence

"the vast extent of the steppes of central asia is enormous"

purpose is to show the vastness of steppes. If we are saying "the vast extent" then its understood that "its enormous". its seems quite awkward as well as unreasonable to say the same thing twice in a sentence, that's why I changed it into
The Steppes of Central Asia is vast/enormous.


The second sentence was
Nobody didn't ought to lose their way so easily in a small town.

I removed didn't and wrote ought not because whenever ought is used as a modal verb, we make it negative by adding not after it.

I did not make the sentence negative, the given sentence was itself negative, but it was wrong because didn't was used there with ought. I only corrected it. (read it, I tried correcting it) and I think i corrected it correctly.

I think I've made myself clear, but you can well differ in your opinion