New to BBT

I have decided to try and react bbt and use OPKs this month but if I’m being honest, I have no idea how bbt works!! I’ve done a lot of research and it says I should do it at roughly the same time everyday and before I even get out of bed. So I’ve been testing between 6-6.30am as this is when I get up for work but sometimes I get up for a wee in the night and this can be an hour before I get up so I hope that doesn’t mess it up 🤷🏼‍♀️ here is my chart and I’m wondering if anyone can explain what the arrows mean on CD5 and CD7

Thanks so much for any help and guidance 😬