+1 for yhe NRA Basic Pistol Course
It is designed for entry level shooters. Like any other activity the fundamentals are needed before you can move on. The NRA Basic Pistol will show you the basics.
Bad habits are hard to break. As a case in point at least a third of the "experienced" shooters that take my Basic Pistol course only because they have to for the CCW permit have a very poor grip, and their marksmanship reflects it.