You might be refering to "under the cover of darkness", which is an expression that means the darkness hides the activity.
It would really help if we knew where you were trying to fit in the expression and why you felt it appropriate.
Whilst most people here would not general mind help you write a letter or at least helping with grammer, you should at least make a start.
Without knowing what the bursary is for or why you should receive it we would really be in the dark as to where to start.
You do not necessarily need to put it in quotations but it is important to make clear when you are referencing someone's work. It should be clear when there work starts and stops. If you are going to paraphrase something again you should make it clear and reference the original work.
It would probably depend on whether the report had several items that someone might have a problem or if it might be the whole document, in which case I would prefer content.
As Anglika says there is probably lots of different thoughts on this point.
Depends on how you want to go?
Happy to be leaving or sad.
A colleague of mine wrote a letter. "Thanks for the pension - I'm off then"
Seriously though the tone will depend a lot on you and whether you want to come back in the future or at least leave it open. If not something simple...
When is your exam starting?
What time does your exam start
Of course if it is an exclamation question, when you want to confirm something you think you already know.
When is it your exam starts?
but would still read better asking for the time if that is want you want.