First, remove back of watch, Second, near edge area where stem is located there is usually a screw or button (depends on brand or model)that holds stem in place. Either unscrew screw only one or two turns or push button while pulling on stem and it will usually come out. You really need quality watch repair tools (loop, screwdrivers, case openers, etc.) to work on a watch properly without damage.
Jesse, June 2006
