Sublist on Excel

Question

I need a list in Sheet1 of the Op# of just the individuals in Sheet2 who are under the age of two. The example is below. If you can, briefly explain what the formula does.

I tried copying an array formula using index, tiny, if, and row, but I am unable to modify it in my worksheet since I don't understand what the formula is doing.

Answer 1

Try using this formula in sheet 1 

=FILTER(Sheet2!B3:B8,Sheet2!E3:E8<2)

The first argument establishes the range to return a value from, while the second argument establishes the requirements.

When the number of rows from sheet 2 is returned, the formula should immediately expand vertically to that number.