Helppp... first time using Ovulation Test

Ken • Thu, Jul 13

I'm not sure if I am doing this correctly. My period was from June 28-July 2nd. Glow showed my fertility window staring on the 10th. I have been testing since then && have not gotten a positive OPK. Did I start testing on the right day ?? I used Clearblue Advance && it said 10 day. I was a little confused as if I should have started 10 days from the day my period ended or 10 of this cycle