4X I'm an initiate in commodities trading. Please inform me how to purchase oil futures for an extended time.

I wish to purchase about $50,000 worth of oil futures for approximately a 6 month hold. How does the futures market allow for a long term/medium term hold. What do I have which shows my original purchase price and amount purchased vs. my final selling price and amount owned. Is online trading and purchasing available and if so how is it done and what brokerage house offers the option. Please school me as best you can on futures purchasing of oil as quickly as possible.