4:17 in this video
Dips are one of my all-time favorite exercises when it comes to building your chest and arms.
This movement can be a little touchy on the shoulders, so it's important to have proper positioning.
Starting with arms fully extended and gripping the dip bar, retract your shoulders and give yourself a slight forward lean.
Lower yourself down with control until your arm bend is at 90 degrees.
There should not be any pain throughout the movement, so if there is, you know your positioning is likely off and needs to be adjusted.
The most common error I see is the "rounding" of the shoulders at the bottom position due to a lack of upper back strength.
To increase the difficulty, you can add weight using a weight belt, weight vest or even chains.