Sled Dragging?

This is a very newbie sounding question, but I want to take my strength gains in a new direction, and I see sled dragging discussed a lot here. It’s good for overall strengthening, right?

Can anyone help me understand how to get started? Like (I know this sounds dumb) what kind of sled? And how do you work it into your routine?

And yes, I tried to search for this, but not much in the way of specifics and no pictures!