What breaker configuration should I use for a 240v shed circuit?
Since this would be a sub-panel install, ground and neutral are NOT connected - they are isolated. There is but one bond between them per code, and that one already exists in the system that the power is coming from.

I'd tend to agree with S.P. that your prior experience is either too long ago or too unrelated to what you are doing for it to seem a great idea for you to dive into this, unless you'd care to prove me (us) wrong by actually doing some research and modifying your question. Going into it half-cocked and not actually understanding things like why there are 4 wires and the neutral (grounded) and ground (grounding) conductors are isolated seems a recipe for disaster I'd rather not encourage.