C & P for OSA, IBS, back and knee.

Any insight of how a C & P for any of these will go? I have a diagnosis of OSA already, and have a nexus letter for that as well. I also have a diagnosis and nexus for IBS. Back and knee pain is due to right knee and altered gait, but don’t have a diagnosis or letter for those. I haven’t gone to a C&P exam for over a decade (other one was for MH) so have no idea what I’m walking into. Should I bring my letters?