When looking up a t value in the table how do I know when to use two-tailed probability?

Doing statistics homework and I'm confused as to when I use the "bottom" of my table vs the top. The bottom of my table has values for two-tailed probability, and the top has values for upper table probability.

If I have an alpha = 0.05 for example, and H0: u1 = u2, and HA: u1?u2 and my degrees of freedom is 5, how do I know if the t from the table is 2.015 (upper tail) or 2.571 (two-tailed)?