Theres fret buzz my low E, A, a little bit on D string and G string

I see the bridge has 2 places where you can put a flat screwdriver in there.

So anti clockwise is to raise the bridge, correct?

and clockwise is to lower the bridge?

Also, How do I know which one should I turn to make the corresponding strings rise?
Er...each one lifts up that end of the bridge. Try about a full turn or so to the lower one (bass side), and a smaller adjustment to the other one. it's possible the problem could be at the nut or due to neck relief, but raising the action should help. If in doubt...experiment!