Either way, the bearing won't fit all the way into the wheel - the fit will be too tight. So first, simply set the bearing into the wheel.
Next, press the bearing down into the hole, applying pressure on the outside metal rim of the bearing. DO NOT press on the shield, or the center of the bearing. You should be able to press the bearing down to where it is flat with the edge of the wheel.
Repeat this process with all 8 bearings, putting one on each side of each wheel. I recommend having the shielded side of the bearing facing out on each. If you are using Spacers, make sure to put one in each wheel, between the bearings.
Interesting Fact - several pro skaters turn their bearings with the outside shield facing in, so you can't see what brand of bearing they are using. This happens because while they may be sponsored by a certain company that makes bearings, those bearings might not actually be the best ...
