Stand with the front wheel between your legs and 'tweak' the bars in the direction you want them.
That's the redneck way I do it.
The long version from FZOA....
There is a correct way to install the forks. And it does involve the axle AND the pinch bolts.
First get the forks as close as you can "same height" in the triples (just snug tight), so that the axle (no rim yet) installed " can slides in through the forks and spin into place SMOOTHLY". NOW lock down the forks in the triple clamps.
Next install the rim and tire. Leave the brakes off or night tightened yet.
Torque the axle (which locks the rim and spacers on ONE side). On most bikes, this is the clutch side fork.
NOW.....PUSH the not clamped fork (that has the pinch bolt at the bottom.....brake side fork) IN toward the rim as far as it will go............and let it move back on it's own. "LOOK" at where the fork is in relation to that end of the axle. Maybe measure if needed.
Next .......PULL OUT that same fork AWAY from the rim.....and let it move back on it's own. Again "LOOK" at where the fork is in relation to that end of the axle.
SPLIT that distance so the forks is centered.
This ALIGNS the two forks in the center of there seals and fork guides.
NOW.......lock down the bottom pinch bolts. Now you can install the brakes ,etc, and ride.
I learned this procedure from LEE at TRAXXION DYNAMICS when I was trained at their factory.
Your forks will perform at their best. This does make a difference.