If you stand over the engine on the relavent steering side and look straight down, near the exhaust manifold is the box. Adjustment screw is on top of the box.
MAKE SURE the exhaust is cool before you begin.
The hexnut is hard to reach but can be done... saying this, some people will actually remove the wheel and the tierod on that side and do it from the bottom but for me, I would rather go in from the top and have the grazed knuckles
There are different makes of box but you will definitely need a 17mm open ended spanner for the big hexnut and depending on the box make, either a flatblade screwdriver or a 4.5mm allen key for the adjuster.
My advice is to initially adjust a 1/4 turn. If steering is too tight and doesn't center properly after adjusting 1/4 turn, loosen off in very very small increments and re-test.
Hope this helps.