I am a beginner. It seems to take forever to model a few simple I beams (shell elements) and assemble it into frame. There has to be some other better and faster way to do it.
if I understand correctly you want to create an assembly structure consisted out of many "I" type beams. The fastest ways to do that are 2, in my opinion:
Way I:
draw the assembly geometry using lines and in property module assign a section using I profile dimensions
Way II:
create your assembly geometry using CATIA and after that import it into Abaqus either as a combined geometry (single part) or as multiple parts.