To convert moles to grams and grams to moles, you'll need the molar mass of each compound. The amount of the substance that is known will be multiplied by a conversion factor (a fraction of equal amounts) that will allow the given units to be cancelled out. Molar mass, or grams/mole, is a conversion factor.
If you are converting moles to mass, moles are the given unit and your fraction has the formula mass in grams in the numerator (top) and 1 mole in the denominator (bottom). Essentially you are multiplying by the value of molar mass and changing the unit to grams.
If you are converting mass to moles, your mass has to be converted into grams first. Then grams are your starting unit and your fraction has 1 mole in the numerator (top) and the mass in grams in the denominator (bottom). Essentially you are dividing by the value of the molar mass and changing the unit to mol.
However, since this is a skill that will build, practice writing out the problem in the show your work. (These skills will be the two ends of a stoichiometry problem that should be written out.)