technical details vary and honestly matter little. what matters more is what people do with these things, and that's what's explained

Its just an entry in a ledger. It says something like, "blandfordforever sends courageousstep 1 coin" along with a cryptographic signature from blandforever that validates the transaction. This means you now have and can transfer that coin to someone else, provided that you have the key to sign the appropriate transaction. That's all it is.

The miners are all competing to sign a "block" of transactions onto the ledger by figuring out new correct answer to a math problem that's determined in part by a number from the previous block. They are rewarded for this by being able to send themselves a preset number of coins in this new block they've signed. Transactions aren't final until they've been added to the blockchain by this mechanism.

A central part to it is that each coin is defined as a series of transactions, not the other way around like with real world items. For example if a new Bitcoin is mined, that's described as a transaction from no-one, to someone.

If your interested in learning more about the math behind Bitcoin and how it functions at a lower level I'd recommend reading the original white paper for it