Put the phone in flightmode and activate only wifi (no, this is noot the same as switching off BT )
If you want a controller get a wired one
Do not fly higher than 10-15m unless conditions are really good and you know what you are doing (very few actually do - so accept the risk is yours). Same for flights beyond line of sight
If there is any wind: take off prop guards and stay at least 1.5m high or Tello will be blown away
Do not fly at night or over water
Welcome to the forum.
I hope you will find our site helpful and look forward to any input , photo's/video's you might post .
Don't be shy and ask anything if you can't find it by searching .