"It is necessary that you do not read that newspaper."
Translation:O gazeteyi okumaman lazım.
It's not ungrammatical, but it's definitely kind of long and awkward. The problem is that they're trying to teach the "okumaman lazım" construction, and the ways that most English speakers would actually express this idea ("You may not read that newspaper." "You can't read that newspaper." "Don't read that newspaper." "You aren't allowed to read that newspaper.") wouldn't be accurate translations of the Turkish sentence. They get the idea across, but the words are way off.
So they've gone with the literal translation, which I think was a good call: it might be awkward, but it avoids the confusion that would come from a non-literal translation, and makes it a lot easier to see what the different words mean.
okumaman... I really find that confusing. any help as to why the use of that word will be appreciated