This is a very quick video to show how to pack a wheel bearing with the palm of your hand. I prefer packing a bearing this way because you can ensure the grease is being pushed correctly and thorough through the bearing. However I do mention a grease packer that you can buy as well as a bearing race seal installer set. I will supply the hyperlink photos below. There are a couple of extras in this video like how to drive a bearing race in and how to install your grease seal.
Wheel Bearing Packer
Bearing Race and Seal Driver Set