[timenova]

What's the best resource to get started with FreeBSD for someone who's never used any BSDs?

I want to experiment with FreeBSD on a spare Raspberry Pi for now.

[deltarholamda]

You'd be happier with a virtual machine I think. Last time I put FreeBSD on a RPi it was less than satisfying, though to be fair it was a Pi Zero and it was quite a while ago, so support was very early.

The FreeBSD Handbook is a great resource. Read it and see if it tickles your fancy.