You (a 'node') have a file of transaction on your computer (a 'ledger'). Two accountants (let's call them miners) have the same file on theirs (so it's distributed). As you make the transaction, your computer sends an email to each accountant to inform.
Each accountant rushes to be the first to check whether you can afford it (and be paid their salary "Bitcoins"). The first to check and validate hits "Reply All"; attaching their logic for verifying the transaction ("proof of work"). If the other accountant agrees, everyone updates their file.
This concept enabled by "Blockchain" technology.