Many times the moment capacity is determined by the local code in your country.
Say in Europe (EC3-steel), the code says for the simplest form of bending (only one axis) that the moment capacity is Mcrd= Wpl*fyield/gamma (for Class 1 and 2 sections).
The Wpl is the plastic section modulus (see internet for more info on that), fyield is the yield stress of the material, and gamma is a partial safety factor.
The local AUS code is AS4100, and that would give the information you need, if you are based there.
Young's modulus is Elastic Modulus in the Solidworks material properties.
The maximum moment for your HSS in bending doesn't technically factor in the moment of inertia. The moment of inertia comes into the play if you were trying to calculate the bending stress or maximum deflection in the beam. The code will dictate what the allowable capacity is but many times the code will specify an allowable deflection in terms of the length of the beam such as L/360.
And you'll want to make sure the Elastic Modulus and Poisson's ratio are accurate for any materials you plan to use in Simulation
Hope this helps,