Start by taking your wheel out of the bike

Loosen the two 1.5mm grub screws on the non-driveside endcap by turning them counter clockwise

Once the screws are loose you can adjust the bearing preload

The non-drive endcap has a let hand thread, so turning it counter-clockwise will tighten the hub

Turning the non-drive endcap clockwise will loosen the hub

Tighten the endcap so the bearings no longer have play in them, but such that they also do not have excess drag

Most of the time these adjustments can be accomplished by hand, but 17mm and 18mm cone wrenches can by used on the endcaps as needed

When you are happy with the adjustment, tighten the 1.5mm set screws to 1.5nm