With pans that have a non-stick coating, you want to add your fat (butter or oil usually) before you heat the pan.
With stainless steel pans, it is the opposite. You want to heat your pan up and then add your fat.
If you do either of those in the wrong order, you’ll get food sticking to your pan.
That really covers most people’s problems when cooking with stainless steel. They don’t wait long enough to have their pan heat up before they add their butter or oil.