How do invasive species take over?

Why are there Burmese pythons and chameleons in the Florida Everglades? We might not know how those animals arrived but they are causing damage to the natural ecosystem. An invasive species out competes native plants and animals in an ecosystem. So how does this happen? But Why travels to the Everglades to learn more about how and why species end up in places they shouldn’t. Plus, why are we sometimes told to kill invasive insects like the spotted lanternfly?