Opk timing

Jenny • Hi! I`m Jenny. My husband and I are expecting twins in Dec. We have a 2 yo girl and are now adding 2 more girls to our family! I`m looking forward to using this community for support!
When using an opk, do you test more than once a day, or just the same time every day? I'm not sure if I should test again after several hours. I expected to see an lh surge today and it was negative.