Clear blue advanced digital opk...HELP

Just wondering when is the best time to test for these....I know instructions say FMU but I have been reading some ladies test later in the afternoon and twice a day....should I test in the AM & PM on flashing smiley faces?? just confused need a little help ladies first time using these and I test tomorrow 🤞🏽 Thank you ladies ❤️❤️❤️