>>63866672you get a call-up notice on the year you turn 18. At the call-up they do a basic health check and an interview to hear where you'd prefer to serve.
later you'll receive mail telling you what service branch, which brigade, which platoon and so on you will serve in.
what role you end up getting determines how long you serve:
165 days for basic roles like infantry
255 for specialist roles like mitarly police and medics
347 days for everyone else, like NCO, ROs, crew members and so on.