Led watch, how to change time on it?

i have an led watch i just got but his has two buttons and i cant figure out how to change the time. also if i get the display to come on its only there for a few seconds then goes blank again,,, is that normal? this is the... show more i have an led watch i just got but his has two buttons and i cant figure out how to change the time. also if i get the display to come on its only there for a few seconds then goes blank again,,, is that normal?

this is the watch
http://www.miniinthebox.com/black-silicone-band-square-frame-unisex-red-led-sports-wrist-watch_p194832.html
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