As an assignment,

1) Choose Benzene and Toluene mole fractions that do not add up to 1 
   Check how DWSIM normalises when you press Accept Changes button

2) Go to the page where you defined mole fractions
   Check what the Normalize button does when the Total is not 1
  
3) Go to the page where we defined the molar flow rate
   DWSIM automatically displays equivalent flow rates in other units
   Check if these values are consistent

4)Create a stream consisting of Benzene, Toluene and Xylene
  Carry out the previous assignments for this stream also