Sorting Data from 2 sheets, one sheet which is already sorted
 

I have two sheets, one sheet is fully sorted by reservation and voucher
numbers (some were also deleted), but I have data in another sheet that I
need to put into the first sheet. This data has coresponding reservationa and
voucher numbers. What I need to do is take data from the second sheet and put
in the first one in the right order, but I have no clue what function I am
supposed to use. Please help.