An ergonomic setup ensures that you are using your computer in a way that will not injure or strain you in any way. As you will likely be sitting/standing at your desk for up to 8 hours it is crucial to not become complacent with the layout of your desk.
Tips to remember when reviewing your desk:
Eyes should be level with the top of the screen
Eyes should be an arms length away from the screen
Upper legs should be parallel to the ground
Feet should be either flat on the ground or on a slightly angled foot rest
Shoulders and arms should be parallel to the ground
Lower back should have support
You should be able to comfortably sit up straight