For B Rating all you need to do is pass a physical involving blood pressure, cholesterol, back strength, lung capacity (all pretty standard) and then a 3k walk with a 10kg pack in 30 minutes. you definitely don't need to be that fit, but, just not very unfit. Something along those lines. For a rating you need to do a 20kg pack for 4.5ks in 45 minutes. The hardest part is getting past the initial screening agency. They are interested I'm if you have any skills/trades/licences as when burn season is off (seems to be getting longer each year) there's plenty of fire track, verge, and maintenance work to do around the parks, bases, and wherever else. If you want any advice on your app PM me, I've moved interstate but worked for DENR for a couple years.