In the simplest example, when you have a closed system where part of the system starts out warmer and the other part starts out cooler, it’s fairly intuitive to understand why entropy will usually increase over time until it reaches the maximum level. When two molecule molecule of gas collide, a high-energy (hot) molecule and a lower-energy (cooler) molecule, the most likely result is that some energy will be transferred from the warmer molecule to the cooler molecule. Over time, this process will result in the temperature equalizing.
In the simplest example, when you have a closed system where part of the system starts out warmer and the other part starts out cooler, it’s fairly intuitive to understand why entropy will usually increase over time until it reaches the maximum level. When two molecule molecule of gas collide, a high-energy (hot) molecule and a lower-energy (cooler) molecule, the most likely result is that some energy will be transferred from the warmer molecule to the cooler molecule. Over time, this process will result in the temperature equalizing.
The math behind this process and how it related to entropy isn’t that complicated, look up the Clausius theorem. https://en.wikipedia.org/wiki/Clausius_theorem