Theres only one stupid question in the world. and thats an un-asked question.
Metering is finding the best setting based on the available light. by using the cameras various metering modes or a light meter or whatever
In P, AV,TV and set modes like sport landscape if your camera has them.. then your camera will do the metering for you.
When you read people are doing the metering then they will be shooting manual and therefore getting the information themselves.
Example. I 99% shoot manual. I will find a nutural colour.. grey if I can or when shooting football I use the grass... I point my camera at it and note the setting the camera uses for exposure.. I then dial these in manual mode.. then when I am shooting the players in black kits and white kits and all manner of colours and have white seast in background or dark blue... it doesnt fool the camera into different settings.. I get a good exposure no matter what because I metered off the grass..
While using manual the exposure will show over and under exposed... I ignore that because I know thats the camera being fooled wiht all the different lighting... every now and then I point at the grass and see the exposure meter is bob on...