What if the next bitcoins hash is  63 zeros followed by 7   000...0007   unlikely but possible right, what next???

Can you tell me what the algorithm is in simple English? i.e. what is the exact algorithm to run and how does one go about it without the use of specialist software? Thanks Tim

Can you help in answering the following questions:-
1. What is the actual algorithm?
2. I'm told a coin is mined every ten minutes, how is this controlled since the number of people mining varies during each day?
3.Why / how does the algorithm become more difficult with time?
4. If new coins are being mined or discovered, I take it not all 21 million currently exist?
5.If 21 million don't exist at present how can we be sure they actually exist and who knows what they are?
6. Why can't it go beyond 21 million, surely there is another solution to the 21 millionth blockchain?
Thanks
Tim