to break H-H bond = 436.4 kJ/mol
to break F-F bond = 156.9 kJ/mol
to make 2 H-F bonds = 2(568.2 kJ/mol)

But which energy is going in and which is coming out?

The first two steps are endothermic; energy is required; we give them + signs.
The last step is exothermic; energy is released; we give it a - sign.

To get the overall change in enthalpy, DH, we add the values to get
-543.1 kJ/mol. The actual value as measured experimentally is -543.1 kJ/mol!!! (per mol of what?)

One more time.....