Wondfu opk timings

I'm sorry if this question has been asked but I'm just starting on opks n my Dr didn't tell me how to use them. So, I know we're supposed to test it daily until we get our period, but are we supposed to check it at certain times of the day? And, more than once daily? I leave for work at 630a and am rushing to get out so it's easier for me when I get home arOund 630-7pm. Help!