Hoping someone can help.
I suggest you learn how Bitcoin works. How to trade (buy or sell it), how to store it, How to mine it and how to avoid scams It isn't hard.
Start with this introductory pages.
https://bitcoin.org/en/http://bitcoin.wiki/https://en.wikipedia.org/wiki/BitcoinIs Legalminner.com a real thing ?
Not it's not. It's scam. Consider all cloud mining to be scam. It's useless.
Someone “helped me set it up and buy bitcoin (I think) but then started asking me to pay them money to withdraw my profit.
So I backed out. But I’ve sent a bit of money somewhere, I think to this legalminner website so I’m wondering if it’s a scam or if it’s real and maybe I can learn to use it and somehow get my money back ??
Well, that someone whom I believe was even a stranger was a scammer.
You could try to contact the police or hire a company,that could track down the BTC transactions(if the scammer isn't using a BTC mixer),but I don't think that you could get back your money.
Reporting to police won't help OP. he will waste way more money trying to trace the scammer.