Your explanation about the very example you gave about the betting of a foot ball game is quite a good one and will be understandable to any individual who reads it. This is because data from outside the chain. That’s the teams they have selected and the amount of money they have staked or placed will be collected by the oracle and the taken into the chain for validation and processes. After which a smart contract is formed. So it the smart contract that will be able to finally execute the outcome of the bet. All the best ☺️