Identify an LCFE accredited dealing member firm (DMF) of choice and open a client account with them
Dmf will open a cscs/trading account on your behalf.
You give a mandate/instruction to your DMF to buy commodities on your behalf at your chosen price, quality and quantity. You deposit the total value of the a you want to buy in your brokers trading bank account
Your broker buys on your behalf from another client through their broker on the exchange
Once the transaction has been concluded on the exchange your money will be moved from your broker’s bank account to the seller’s account
The seller’s Commodities now belong to you. You can now pick up your commodity at the storage facility or choose to resell on the exchange for a profit