So the molecular mass is the same as molar mass in simple terms to find it you just add.
For example NaCl,
the molar mass will be The mass of Na + the mass of Cl . The mass of NA is 22.98, and the mass of CL is 35.45 so when you add them the molar mass will equal 58.43.
That is molar mass .
Another example H20
In this case, if theres a subscript in the formula include it . This means the mass of H (hydrogen) is 1.00784, you will times that by 2 because the subscript is 2
So the MASS of H2 is 2.01568. Then you add it to the mass of oxygen which is 15.999 . Because the oxygen doesnt have a subscript you dont multiply the mass by anything . So the molar mass is 18.01.
Now moles , is just the coefficient basically ,
so in a chemical equation for example you have 2Na + Cl = 2NaCl (sodium chloride)
The moles of Sodium alone will be 2 due to the coefficient , and the moles of sodium chloride will also be 2 as they happen to have the same coefficient
Another example
2 Fe + 3 Cl2 = 2 FeCl3
The moles of Fe (iron) is 2 , the moles of Cl (chlorine) is 3 and the mole of FeCl3 is 2
Basically if they ask for the mole of an element or compound just look at the coefficient