If 17.0 g of sodium chloride are dissolved in water to make 0.5 L of solution, then what is the final concentration of the solution?

Answer 0.6 mol L

I don't get this. I know that
1 mol / 22.4 L

You're on the wrong page but you have the right idea. The 22.4 L/mole is the volume of an ideal gas at STP and doesn't have anything to do with concns of solutions.

Convert 17.0 g NaCl to moles.
moles = grams/molar mass

Then M = moles/L.