Step 1, it's for your mouth, not your bottom...I used to think a 'basal' thermometer was for your bum, and didn't get one for ages as I was put off. Put it under the tongue obviously.
I chart on paper. I find it easier. Just make a spreadsheet with days of month and cycle days at the top. Then I have temps down the side and at the bottom down the side things like 'period', CM, ovulation pain, etc.
Personally I don't trust apps...I chart on fertility friend and it gives me a different ovulation day to Ovia, which I think is generally more accurate but doesn't have a BBT charting option.
My sleep is dreadful...I wake up all the time. It still seems to work. It's best if you have at least 4 hrs sleep before but I don't always. I take it different times when I remember to when I wake up in the early morning.
A good book about temping is 'Taking Charge of Your Fertility'. The temps for 6 days before your luteal phase should all be lower than your temp when it goes up for luteal phase. You want your luteal phase to be 10 days or more. My temp doesn't go up the day after ovulation but several days after and for some women it creeps up slowly.
In my opinion one of the best things about temping is that I know exactly the day AF will start as the temp drops. You also don't really need to do a pregnancy test because you can see by the temps going down before AF that you are not pregnant.