Removing push style stems is generally very straight forward and not very difficult. You will need to remove the back from the watch to begin. For help with this see our How To Open a Watch Back article. If you are ever unsure about any aspect of working on your watch we recommend bringing it to a professional watchmaker to prevent damaging the watch.
Locate the dimple. Like in these two photos, each movement is different and some watch stems must be in the time setting position for you to be able to see the dimple.
If you cannot locate it, pull the stem in and out to help you locate.
While pressing down on the dimple remove the stem. The stem should slide out of the movement without a great deal of force.