For learing Metatrader there are user guides, articles in this website, and a million videos on YouTube and much more that Mr Google can tell you about.
All the commodities, Contract for Difference - CFD actually, are handled by different brokers. Some brokers do them and some do not. Some only do the majors and some have more tan a dozen. The bróker you deal with will have their branded Metatrader with all the CFDs that they handle and that is where your data will come from. Metatrader is a platform but the brokers handle the trading.
It takes time. Use demo accounts and learn everything you can before you start using real money.