The story of Solo Leveling is about a weak hunter named Sung Jin - woo. In a world filled with dungeons and monsters, he starts off as an E - rank hunter, which is the lowest rank. But he gets a mysterious system that allows him to level up and become extremely powerful over time. He faces various dangerous dungeons and strong monsters, and gradually rises to become one of the most powerful hunters in the world.
You can start from the chapter where the anime ended. Usually, there are online forums or manga communities that can give you the exact chapter number.
The Solo Leveling anime sticks closely to the manga. But there are instances where the anime might condense or expand certain events to create a more engaging viewing experience. The key plot points and character developments remain largely unchanged, though.