The English should be "Later, we will do the examination."
If you think something is wrong, hit "report a problem". Pointing it out in the comments it likely won't be seen by the right people.
When I choose "the English sentence contains an error" or is awkward, etc., there is no place to suggest another sentence. That is why I put it in the comments.
You can select multiple options. I also hit other and type my suggestion in the box.
The word order "Tutafanya mtihani baadaye" is wrong ?
No it's correct.