First time taking a breath test

It’s gonna sound pretty silly, but I thought I’d just ask since I’ve just got one shot of doing this. I can’t really afford to make any mistake mistakes.

So my breath test has arrived. I understand that you’re meant to do a specific low FODMAP diet the day before the test and then 12 hours you’re meant to fast which is what I understand.

my question is in the morning of when I start the actual test I did read somewhere that you’re supposed to brush your teeth to prevent increasing a false level of bacteria as part of the test as I want to ensure it accurate as possible however ChatGPT has told me to not brush my teeth.

For anyone that has done a breath test, can I please ask a clear and concise step-by-step of what it is you’re supposed to do and what you’re not meant to do.

My test kit arrived today, so I’ll be doing the diet on Saturday and then the test on Sunday