I'm having a really hard time grasping the concept of how to take on setting up both Metrics and Kerning. I understand that metrics is all about adjusting the left and right side bearings, and the Kerning is used to make that space even more snug for combinations like AV. But what is really getting me messed up is how to approach setting up my typefaces metrics what do I reference each glyph to and how do I know that my metrics are where they should be?

Are kerning and metric classes usually the same?

What is your approach for setting up metrics and kerning for a typeface generally?