Hello. I am a Chief Clerk currently working as a Management Services Officer (Finance Log Position). I am AirForce on an Army base (purple trade as we are ref to). Here are some very BASIC facts:
Finance Officer(Capt) - Basically you would be working with budgets and ensuring you keep the Commander out of Jail
And you would ensure to the Commander (Base Commander) that all are making financial decisions in a very VERY responsible manner and that all are trained and aware of their responsibilities - after all it is the Tax Payers money we work with. As a Lieutenant you would probably start off as an Accounting Officer (usually in charge of a Cashier and in some cases an Orderly Room full of Clerks doing pay and admiinistration)
HR - We call this a G1 in an Army Headquarters set up or an Administration Officer in other Units. Basically the person in charge of ensuing all paperwork is done properly and staffed correctly, etc, etc. The Admin O would have a fairly large staff under him or her to ensure, again, the Base Commanders Base is properly being taken care of (Administration, Pay, etc)
Supply and Transpost - Not overly versed in these field but basically its Vehicles/transportion/management of .... Or Supply (clothing anything storeable, movement of these supplies, etc)
Air vs Army vs Navy = Airplanes/Static Base/Squadrons 8-4 vs Soldiers/soldiering/Static Base/Field Units 8-4 or sometimes on tour 6 mos or in the field vs Ships/Static Base 8-4 or away for long periods on a Ship
Hard to compare but it looks like the Air is the cushier than the Navy then the Army.
Pay and other information can be found at your Recruiting Center. You DO have a right to ask about the pay as this IS a big factor (especially when you may have mouths to feed) - EGS is talking about other factors you will have to be aware of (subordinates "workers", QOL "quality of life" after your in and become a full fledged officer and these items you will learn when becoming an officer "Im married to one
. In fact, I think you will find the pay is in many cases BETTER once you get to a certain level than many jobs in civilian life.
GO and see recruiting - get as much material as you can from them, ask about the three options Air/Navy/Land - I am sure you will make a very good choice - I wish you luck and hope you find the CF as a choice!