Plain advice on the equipment behind a store: what to look for in an office chair, a monitor and the rest of the desk, and how to set it up so it fits the person using it.
A good office chair is one that adjusts to the person sitting in it. Here are the measurements and features to check, and how to set the chair up at the desk.
For most office work a 24 or 27 inch screen with a good stand is the sweet spot. Here is how to choose size, resolution and connections, and how to position the screen.