OK what do you mean you never put gas in it before??
you sure you put fuel in fuel tank and not oil /motor?
I know this should be a simple deal, fuel tank is a fuel tank, but if you never done it before, anything could be possible
so want to clear this up
HOW long have you had this ATV
HOW old was the fuel in the fuel tank before you added more to it?
as OLD fuel is BAD fuel and will cause running issue's
MY suggestion to you would be to get yourself an operators manual and learn what does what, so your NOT making larger problems for yourself by causing damage to things
as pressings starter button while motor is running, can do damage!
I would also maybe suggest having someone near you come by and HELP you get it running and maybe show you how some things work too
as it seems like you do NOT Know very much about this atv or atv's in general
and could again end up with larger more costly problems due to lack of knowledge here, and safety is also a concern too!
were all on this forum to help and get help
so don't be offended by this, its meant as advice and help!