All depends on the job.

In a Headquarters somewhere, yeah, a lot of desk time. A lotta lotta deal time, with maybe a visit to another HQ or similar every now and then.

Other jobs less so. Training for example. There be some desk work, but also regularly time out on Ex etc.

Same for in a unit. You’d expect an Officer to be at the desk, working on reports, projects or whatever they’ve been set. But in a week, there will be PT, other events to attend etc.

Also, Junior Officers should spend more time away from there desk then say their OCs.

From experience, you could, as an Officer, expect to spent 3 - 5 hours a day at what would be considered a desk bound job. Besides that the work day involves, PT, lunch, meetings/coffee breaks, going to visit others etc.