wassup I got my first NSR250SE 2 days ago

Hey, when i got my license at the driving school we used the honda CB400 and first gear is very easy to idle. When i first rode the nsr i stalled a few times, do you have to like idle above 3000 to keep it from stalling?

Also when i got it the guy told me to pull back the choke when i kick start the bike and then push it back after the engine is started. do i have to do this everytime?

Also they topped the engine oil with i think catrol or something. I asked if i could put in motul 600 and they said its fine, is it ok to mix engine oil??

do you guys put in regular gas or the higher octane gas (more expensive gas) and when should i change the spark plugs?

Sorry for all the questions, i'm just a noob when it comes to nsr's
Thanks