Position the handlebar centered in the stem clamp and put the faceplate back on.

Retighten the bolts of the faceplate while the bar is in a adequate position with slightly pointing down brake levers, until they hold the bar.

Now tighten the bolts in a cross pattern, starting with upper left going to lower right, then upper right going to lower left. The torque wrench value for this should be around 8 Nm.

Make sure the upper and lower gaps between faceplate and stem body are parallel and with an identical width.