There is 737 grams of mass of NaCl in a package of Morton Salt. NaCl has 58.4g in one mole, so isn't it 737 times 1 divded by 58.4g to find the amount of moles?

Yes, you are correct. In order to figure out how how many moles something is, you have to set up the equation so that the grams cancel out, thus setting it up as 737 g/1 x 1 Mole/58.4g. This will cancel the grams, leaving moles as the result.