SIMPLE TASK-ADDING values from 2 columns in to a 3rd column.

[Chelnak]

I am having trouble with a simple task. Adding values in Column X +Column Y in to Column Z. What is the proper formula, what do I highlight, etc.?

[#2]

@Chelnak 

Let's say the values start in row 2 (perhaps with headers in row 1).

Enter the following formula in Z2:

=SUM(X2:Y2)

Double-click the fill handle in the lower right corner of Z2 to fill the formula down to cells below.

[#3]

Thanks@Hans Vogelaar . I figured it out.