In reality today, many new shooters have a tough enough time paying for a good sidearm, much less paying out cash for formal training (even though it is invaluable).
I was fortunate that, in my career of LE, I was offered almost unlimited firearms and tactical training, and for years was a LE Firearms Instructor for the State. (yes, they actually paid me to be at the range all day... with unlimited ammo).
Thesedays much can be learned from reliable sources on the Internet, Videos, etc.
The first thing I was always taught for shooting was 'STANCE'.
There are two main upright shooting stances—the Isosceles and the Weaver.
The WEAVER Stance is used by LEOs as they are trained to always stand at an angle (bladed) to a subject (weak toe towards target & other foot back at a 90* angle... sidearm is then drawn with holster furthest away from target... sidearm is then brought to weak side with strong hand & joined with weak hand for support. This allows least area of body to be exposed while facing target.
Also, it allows sidearm to be kept closer to the body and allows for weak elbow to rest on body for support aiding in accuracy.
Then, is the ISOSCELES stance (aka the 'T' Stance): face target, feet spread about shoulder width & toes facing target. Sidearm is drawn, brought up to eye-level and joined by weak hand while thrusting sidearm towards target until elbows lock. The locked elbows also allow for stability.
An option to bringing sidearm up to eye-level, is to squat a bit... meeting eye-level quicker.
Neither is the correct or wrong stance, but the best is what gives you performance at the range.
With time, or professional training, you will learn the many variations of these basic stances.
Next will be Grip (L & R) > Sighting (front only) > Trigger Squeeze (bounce) > Draw (practice) > Retention (techniques).
Each would make a fairly thick book to cover everything, to name a few. Best is to learn it right to avoid bad habits & much practice at range and home, both.
If you are good at sorting through garbage, YouTube has a lot of very good info.