App question- chance of pregnancy circle

I’m confused by the “chance of pregnancy circle” can anyone help? I had a positive LH test and the following day ttc 2x. The current chance of pregnancy says 2.4%. Does this mean I did not ttc at the right time? Ideally, in relation to the LH surge tests how many days prior to a positive test and how many days post a positive test should you ttc? I am guessing 2 to 3 days prior and 2 to 3 days post? Thanks for your help!