1. Since you must need the value for moles to find the molarity you have to convert 33.4g into moles.
33.4gNaCl / 58.44gNaCl = .572molNaCl
2. Since you cannot use mL to find molarity, you must convert the value into liters by dividing the value by 1000.
300.00 / 1000 = .3L
3. Now plug in your values into the equation. ( M = mol/L) [ Just divide moles by the liters]
M = .572 / .300 = 1.91M OR 1.91mol/L (Units can be M, or mol/L)