Most ergonomic guidelines for computer workstation arrangements assume that you will be using a desktop system where the computer screen is separate from the keyboard. Make sure that you have a stable working surface with adequate room for proper arrangement. Choose a comfortable chair for the user to sit in and has a good backrest that provides lumbar support. If more than one person will be using the computer, consider buying and a chair with several adjustable ergonomic features. Place the computer monitor directly in front of you.
Good posture is the best way to avoid a computer-related injury.
Make sure that the user can reach the keyboard keys with their wrists as flat as possible and that the user's elbow angle is at or greater than 90 degrees to avoid nerve compression. Avoid overreaching for mouse use. Make sure the user sits back in the chair. Also check that the feet can be placed flat on the floor or on a footrest. Make sure that those things the user uses most frequently are placed closest to the user so that they can be conveniently and comfortably reached.