As for relay, I recommend strfry: https://paulmillr.com/demos/qr/

As for Lightning node, there are two: Core Lightning (aka. C-Lightning, CLN) and Lightning Network Demon (LND)

CLN: https://github.com/ElementsProject/lightning

LND: https://github.com/lightningnetwork/lnd

I use CLN - but LND seems to be the one with more new-fangled stuff, so it's worth taking a look at both.

Once you have your node running, all that's left is to make a channel with someone. There's plenty of people that can help you with that.

Depending on wether you used CLN or LND, your nostr setup will wary a little. But, one step at a time. Feel free to poke if you have any question. I am by no means an expert, but having done the trip myself, there ought to be a thing or two I can help with!