Entered the second round interview but failed it back in Nov 2019. The person that conducted the day 1 activities was a new hire for about 9 months, and he told us during an honest conversation at the end of day 1 that he worked till around 11pm most of the time for the first 6 months because he was so busy trying to learn the ropes. Starting pay averaging 4.5k for FSO regardless of track, though I'm not sure if the pay will scale according to your work exp. It's also pretty difficult to get in - about an average of 1/4 of applicants pass the first round and 5% of that pass the second if I recall the numbers correctly.

According to him, not a lot of onboarding except for the most basic first 2-3 days HR spiel if you are really unlucky because it's up to the senior before you to guide. For him, his senior left for the 3 year overseas posting about a week or two into his job so he had to learn a lot on the job by asking around. I honestly can't remember if his department gave him any support during his first months since it's been nearly half a year since I went for the interview and I don't remember much of the conversation, but it is likely they did so even if it was in a limited fashion. Can't remember if your role rotates after every 6 year cycle of local+overseas or if its on a yearly basis.

Basically, you should enter expecting the worst while hoping for the best as with any other job. The FSO role is pretty backbreaking, but you'll at least have a meaningful career and never stay bored for too long.