You have come to the right place for information concerning your new/old TTR.
Lots of folks here to help. I know this will be a good source for you, as it has saved me lots of effort trying to figure out stuff on my own. Start off simple by changing the motor oil & filter, check brakes, "burp" the forks (just under handlebars) so you will know where you are at out so it is safe to ride without harm to the bike and especially to you.
All you have to do is hollar, and someone will usually answer back. GOOD LUCK!!