For the third column:
[use the first image attached]
have you ever learned the circle of fifths? (this is for the key) It is the above attachment. You weren't asked to construct it, but drawing it is a good exercise for many music students. The keys on the outside are most important for the work you've been assigned, just match them to the key signature. For example, two flats would be a Bb major, in the major scale, of course. Four sharps would be an E major.
The keys shown on the inside of the circle are the relative minor of the outside ones. For example, C minor has no sharps or flats and its relative minor is A minor.
∆∆∆
For the second column:
we can start our work on the closest note to us, example:
[use the second image attached]
I really hope I've helped and explained well!