Much of a much-ness really. Substitute Inf for Cav/RMP/RLC/RA/etc
Your job as a pl comd is to lead your platoon, your Pl 2ic will mentor you beyond what you learned on your YO course until he/she deems you competent enough to be let loose with the reigns.
Paperwork wise, the buck stops with you. You are the Pl/Tp G1 lead. You can be as ally as you want, but if your blokes’ reports are late you’ll instantly lose respect, from your soldiers, OC and CO, especially if it means if one hasn’t progressed to a board.
You’ll have various reports to do, Annual Appraisals, discipline, medical etc, and your first company 2ic and sergeant major will let you know what needs to be done when.
However, to reduce an officers role to that of a paper shuffler does the role a huge injustice. It is a true privilege to lead soldiers, especially on operations and Pl Comd is the job in which to do it. The paperwork is the shit bit, but the rest of it more than makes up for it.
You do the leadership bit. Same across the board, as said above.
RAC subaltern: get on the tank park, and get stuck in. You will get to know the machines, and, more importantly, the people that work them.
If you go CR2, then double this effort. In fact, treble it. You will find it worthwhile.
I wish you all the best with your future aspirations.