Clear a spot to work and make sure that there is a small towel covering the table top so that you can see anything that may drop or pop out during the process of changing the band.
Work with the back of the watch towards you. Find the point where one side of the band is attached to the watch, use a magnifying glass if you have to. You will see a small pin connecting the band to the watch on either side of the band. Carefully use the the forked end of our band change tool to depress the spring loaded pin from the watch to the band and release it from the watch. When the tension on the spring pin is released it may pop out of the band and you will want to take care not to lose it. Repeat this process with the other half of the band.
Take the new band and slip the spring pins into the ends of the band where they attach to the watch. Working with one end at a time, slip one side into the pin hole in the watch body. Use our band change tool to depress the other side of the spring pin and guide it into the pin hole in the other side of the watch body. You will hear an audible "click" when the spring pin pops into place. Repeat this process with the other half of the watchband and other spring pin.