How to earn cosmetics in Warhammer 40K: Vermintide

I spent my first few hours of Darktide slumming it in a prison uniform. The cut-off sleeves did help show off my Ogryn’s bulging biceps, but otherwise it’s a pretty drab look. Where’s my cool chestpiece? Some funky goggles? A pair of tactical cargo pants I can fill with shotgun shells? Until I hit level five, I didn’t have a single piece of cosmetic gear to my name, and had no idea when or how I’d unlock any.

Now that I’ve figured it out, I’m here to share my wisdom (and the good word about our lord and saviour, the God-Emperor) with every other raggedy Darktide convict looking for a fresh shirt.

How do you get Darktide cosmetics?