I used those this past month too. When I didn't yet have ewcm but was within the timeframe of O from past months, I'd test once a day in the afternoon around 3.
But when I started getting ewcm I'd test twice a day. Once around 10am (not fmu) and once around 4. I'm glad I tested twice a day because when I got my positive in the afternoon (which actually was technically negative but realllly close), my morning one was definitely negative.
GL with them I hope they work for you! Don't fret if you never see a full positive, some women won't ever get one (like me). But seeing the progression day to day helps.