Fret the last fret on the top and bottom strings. There should be about 3.2mm or the thickness of a nickle between the string and the pickups. Then fret the first fret with your left hand and the last fret with your right thumb. stretch your right first finger(while fretting the last fret with your thumb) to the middle of the neck(10th-12th fret or so) and press the string down and let it go repeatedly to see how much space there is there. You should have a space the thickness of a medium pick between the topmost surface of the fret wire and the string. If there is more, your truss rod needs to be tightened, less and it needs to be loosened. Do this a little at a time. like 1/4 turn. If you are unsure of doing this, don't.
If all of this seems ok and it still buzzes, it might need a fret job. To check that, hold the guitar flat with your nose at the back of the body and look down the neck searching for any fret that is notably higher or an obvious dip or hump in the continuity of the frets.
Unfortunately you really should take it to a shop for a fret job because if you try it and take one down too far you need to refret it and then you might hunt me down and kill me for telling you to try it yourself.
If this all looks ok, you could try shimming the neck at the pocket but I dont recommend this as it often reduces the area contact between the neck and body and reduces sustain. It probly needs a minor fret job.
Good luck man, hope I was helpful.
me