Mining simply explained:
To be the first to find the next number that fits on Bitcoin's network.
This unique number is the next Bitcoin.
Once it is registered on the network, no one else can add the same number to the network.
The number can be transported to addresses on the network. Whoever has access to the address has access to that Bitcoin.
The person can use the Bitcoin as a means of payment, by sending it, or parts of it, to other addresses.