Bitcoin mining is the process of using specialized computers to solve a cryptographic puzzle, in competition with everyone else on the network, in exchange for the right to add the next block and collect a reward. It's how new bitcoin enters circulation and how the network confirms transactions without a central authority, the practical application of the Proof of Work model covered in \[pillar hyperlink: What Is Bitcoin\].
Miners
Miners are participants running specialized hardware dedicated to solving Bitcoin's puzzle as fast as possible. Today this almost always means purpose-built machines called ASICs, since ordinary computers can no longer compete.
Hashing
The "puzzle" is finding a number that, combined with the block's data, produces a hash below a target value. There's no shortcut; miners must try enormous numbers of guesses per second until one succeeds.
Block rewards
The first miner to find a valid hash adds the next block and receives newly created bitcoin, plus the transaction fees in that block. This reward is how new bitcoin is issued, and it's cut in half on a fixed schedule. See \[pillar hyperlink: What Is Bitcoin\] for how the halving fits into overall supply.
Difficulty
Bitcoin automatically adjusts how hard the puzzle is roughly every two weeks, so blocks keep arriving about every ten minutes regardless of how much total computing power is pointed at the network. More miners competing means higher difficulty, not faster blocks.
Energy
Because mining rewards raw computational effort, it consumes significant electricity, the practical cost that makes attacking the network prohibitively expensive. See Proof of Work vs Proof of Stake for how this compares to alternative models.