Welcome aboard! Just keep a thick skin and don't take offence like so many prima donnas here! Well done- a big hurdle. Enjoy the industry- you will love the job.
Each airline has dedicated check-in facilities for crew (crew room)- usually a place to catch up with a few old friends and exchange gossip! Check-in usually carried out yourself on a computer and paperwork for flight either computer selected or sent over to a printer for you. Facilities to check latest notices and official notes printed up (like 'stop being rude to security morons'). You sometimes find out where aircraft parked. I don't bother- just go out to transport and get taken- You are usually always driven to the aircraft because it may be on a remote stand. Only once have I ever got on an aeroplane and started doing checks before it was noticed that it wasn't quite the right one!
Cabin crew are fully committed to meal service, so there is a pause in looking after you. You normally have to wait until their service is completed until crew meals can be cooked. Sometimes it is possible to have leftover passenger meals. Some airlines allow special crew meal ordering (veggie etc).
I often used to take my own food ex-base, but since Security has been given free reign to rule our lives, they like doing things such as confiscating it now (no liquids). Sarnies OK, but full meals may be a problem. Special diets (veggie, low fat) usually catered for in crew meal selection.
Walkaround done by handling pilot. On long range 3 crew, usually the 'heavy' or spare pilot takes this task. P2 and P3 (when carried) usually swap seats during flights, used for inflight relief on long range. All airlines now only use 2 pilots unless hours extension is required. On complete trips P2 and P3 changeabout to allow practice. Sims are not used for recency training- they are too expensive- only for recurrent Sim training and checks.