Should I cover what is uncovered?

If your story requires some events or circumstances to be not disclosed until it reaches a certain point, then yes, you should withhold that information at the beginning and reveal it when it is time. The genre does not matter, be it a murder mystery, romance, or a YA coming of age story.

Think of the reveal of a certain bit of information as you think of any other event in your story (because it is, just as well as someone getting ill, leaving the town, or getting married), and plot accordingly, that is all there is to it.

Should I cover what is uncovered?

If your story requires some events or circumstances not to be disclosed until the narrative reaches a certain point, then yes, you should withhold that information at the beginning and reveal it when it is time. The genre does not matter, be it a murder mystery, romance, or a YA coming of age story.

Think of the reveal of a certain bit of information as you think of any other event in your story (because it is, just as well as someone getting ill, leaving the town, or getting married), and plot accordingly, that is all there is to it.