If a Casio watch has a display readout that says "OPEN", the watch isn't closed properly. Check if all the parts are inside the watch and make sure the watch is tightly screwed shut. If the watch was serviced at a repair center you should return it to have it checked (for missing parts).
On the Casio website, this model 6054 isn't recognised. With the module number (you'll find it in a small rectangle on the back of the watch case) you can download the manual for your watch here: Timepieces Watches Manuals CASIO