Push the MODE button until you are in step mode.
Hold down the SET button for three seconds. The display will show F-3. Push the SET button and it will show the next value which in this case is F-5.
Push the SET button again and it will cycle to "F-0". Choose your setting.
Release the SET button and it will revert to the STEP display in 10 seconds and the new value will be stored.

Walk4Life pedometers incorporate a user-adjustable step filter. 
A step filter counts a specified number of  steps before actually incorporating them into the total step count. This helps eliminate false steps that occur in a variety of situations, such as traveling in a car, shifting in a chair, or sitting down.
There are three settings:
     >> F-O counts all steps
     >> F-3 counts three or more consecutive steps (also the factory setting)
     >> F-5 counts five or more consecutive steps