I presume you're referring to a chronometer watch?
You need to twist the crown (little screw on the right side of the piece) counter clockwise until it slightly pops out. This is position 1. You need to pull the crown outward gently until you feel a lug sensation. This is position 2. Turn the crown to adjust the 'date' until you reach yesterday's date (one date before what you actually want). Then pull the crown outward again feeling that lug sensation. This is position 3. Turn the crown so the minute-hand swings in the normal movement of time (don't swing it backwards). Keep doing this until the 'date' turns to the current date. Now your piece is set on the correct date and the minute-hand is in the "a.m." Now keep turning the crown until you've reach the current time (noting the am/pm period you want). Push the crown inward to Position 2, then to Position 1. Turn the crown while in Position 1 to wind the spring. How many times depends on your brand, mine is 35-40 turns. Once I am done, push in the crown and turn simultaneously to lock it down. It will stop when it is seated properly.