Navitimer 38

In order to maintain your watch, please do read your manual carefully.  Please be aware that mechanical timepieces are made of a lot of small and delicate parts that need to be treated the way they are meant to be treated.  In general, the only maintenance a watch needs is giving it its energy, winding the coil.  Some watches are hand-wound, and will need a few twirls of the crown regularly, others are self-winding and have a power reserve, so if you move around enough you should have the constant necessary power to have your watch turn perfectly.  Other regular maintenance includes setting the date.  Most watches with a date-function have 31 days a month, and so they will need to be changed every month that has a different number of days.  The more complicated watches with a perpetual calendar won't need this.
In any case, if there's not working properly, or you have specific questions about your watch, please contact a Breitling dealer.