New to BBT

Ashley • Mommy of 3 boys 🧑1 girl 👱‍♀️ and 2 angels 👼
I am on CD 2 right now, I just ordered my basal body thermometer and was just curious on what CD do you start checking your BBT? Any advice on this would be appreciated. Been trying for 10 months no luck. Used ovulation kits, been using preseed lubricant and nothing has worked. Hoping by temping I stand a better chance. Thanks!