HELLO ladies, I really hope someone can help me out here.

December 1 will be my first month trying to conceive and I have been told that the best way to track ovulation is by using a BASAL BODY THERMOMETER? Also I have pcos and every month, I do get positive OPK... but again, i’m told BBT’s are better . So today I went and bought a bbt but i have NO idea how to use it and when to use it and how i would know i’m ovulating ? can someone PLEASE help me out, i’m a complete newbie at this.