Proof of Work is a type of Consensus Mechanism that can simply be understood as proof of certain amount of work done which can be easily verified by checking the end results.
Bitcoin mining utilizes Proof of Work as a Consensus Mechanism. The Bitcoin Network adjusts the difficulty to ensure that it takes around 10 minutes for miners to come up with the correct solution. The solution contains the correct nonce in the “blockheader”.
Proof of Work is when miners find the solution, we can assume that miners have completed the work for that specified difficulty level. The probability of updating the next block is determined by the percentage of total computing power a miner control.
If a miner’s contributes to 30% of the network power, then his probability of winning is 30%. Hence, increasing your computing power will increase the chances of obtaining new Bitcoins.