The golf swing setup is made out to be really complex by a lot of instructors. It's not.
Get behind your ball with club in hand and pick out 2 spots.
The first spot is your target (where you want the ball to land). Make sure that if you look away (which you will), that you can find it again. Don't pick something 2 miles away. Pick a realistic place for your ball to land.
The second spot is 3 to 6 inches in front of your golf ball. Make sure that the ball and spot draw a line to your target. Pick a leaf, or (heaven forbid) put a ball marker in the right place! Don't worry about it, you're trying to get better, and are using the marker as a tool to help you learn to aim better. The USGA Golf Swing Thought Police are busy with someone else, just do it. Try it in the fairway too!
Once you pick the targets, don't think about them anymore. You are lined up, no worries. Move up to the ball and stand upright with your hips parallel to the established target line.
Hold the club in your left hand (lefties please read this with a mirror). Extend arm and club (semi-straight elbow) towards the ground at about a 45 degree angle. Tilt at the waist until the club touches the ground. The ball should be in the middle of the face of the club. If the ball is somewhere else, then MOVE YOUR WHOLE BODY away or towards the ball. If you change anything else you will lose alignment or balance.
What you are trying to do is establish a routine and a position from which you can, via a repeatable golf swing, make solid contact with the golf ball.
Beware the belly trap. You've seen the professionals, and the 18 year olds, with their arms almost vertical as they set up. Well, they don't have a belly, and most of us do. The belly (and loose clothing) can impede and deflect the golf swing. Look at the senior tour. They keep their elbows away from the belly trap. This also allows you to wear something warm on a cold day without getting your elbow trapped by clothing. You could call this setup perfect for fat man golf!
The real reason for this positioning routine is that every club in your bag is a different length. So, we are giving your body and mind a concrete reference of where the ball is and how long the club is. Swing mechanics and body mechanics require some information, and that's what you are providing through this routine.
Now, keeping your waist angle, bring your right hand to the club while bending your RIGHT knee slightly. Take your grip making sure your club head is perpendicular to the target line. Don't change your grip orientation if the club head is not perpendicular, instead rotate the club head and reset your grip.
Now you're ready for the Golf Back Swing.