Inorder to add a block to blockchain and get reward a miner have to successfully hash the block.Inorder to successfully hash the block it should contain certain number of leading zeroes. Number of zeroes is set by the difficulty level. So what is Hashing. Hashing means taking a set of data and converting to a smaller value. Bit coin uses a hash function called double SHA-256. So every data you will get a hash of size 256 bits. Now lets look at a block.
A block contains following
Previous block hash,
Merkle root,
Timestamp
Nonce
Transactions
In this nonce is a random number. So what a mining system basically does is keep changing the nonce till it get hash with required number of zeroes. Once it get required zeroes the block is send to the network to get added to the previous block(block with previous hash) and the network agrees on that and the miner is rewarded.
Eg of hash 0000000000000000000ab8393bne8c06
