At about 6:30 am of Saturday October 7, 2023, thousands of Hamas terrorists broke through the fence of the Gaza strip and moved on armed vehicles and motorcycles invading Jewish communities that surround the Gaza strip.
Starting at about 7:00 a.m., terrorists in the Hamas-ruled Gaza Strip began firing volleys of rockets towards Israeli territory. By Saturday evening, Hamas claimed it had launched some 5,000 rockets.
The article "Israel and Hamas - The facts" by Ashley Church provides an excellent overview of the current war.