j = wksPMP.Cells(4, 4) + 2
Assigning a number to j. j will be the number found on the Viewing sheet cell D4 (=cells(4,4)) and then 2 is added to that number.
For i = 23 To 34
A loop is initiated. With each loop, i is increased by 1. Starting from 23 and ending on 34.
wksPMP.Cells(i, 3) = wksDatabase.Cells(j, i - 20)
The viewing sheet cell C23 will be the same as the value on the database sheet row j (determined earlier) and column i-20 (23-20) = 3 = C.
Go to the start of the loop.