noob, 1st time, someone else's shop... receipy for a weekend w/o the bike.
You can take tire off... with some effort uncoached, but changing a tire, no way.
Take it off, if your friend will change for a beer, cheers.
otherwise run it down to a shop that'll change it for you.
If you really want to do it, get a coach, a couple extra tubes and have fun.