when to BD?

Hi all, this is my 2nd ttc cycle and I'm still not sure when reading my OPKs. yesterday I decided to use my strip opk (CD13 at 12pm) and didn't expect to get a positive reading (also because Glow predicted it to be later at about CD16). On the same day in the evening I got my peak on Clear blue Advanced Digital. I know someone say not to test anymore after a positive but I did anyway (CD14 at 9am) and got another that looks like a positive too (or doesn't it?) My question is whether I should BD everyday for 3 days (CD13-15) or can I wait until CD15 to BD for more optimum sperm production and since I may not be ovulating until 12-24h after a positive opk and in this case should I take the first reading or second reading as the positive? sorry I have so many questions! TIA