First, take off the wing nut and washer that it comes with.
Take the priming piece and place it on the tube where the filtered water will eventually come out.
Turn your water on at a slow rate. You don't want it too high, or you will make a mess when you go to push the priming piece on the faucet. Water will fly everywhere.
Press the filter with the priming piece up to your faucet firmly. Hold it there until the water starts seeping out of the filter. The goal is to see water come seeping out of all the little pores.
You may also start seeing some bubbles forming on the filters. That's ok; just keep holding the filter up with the priming button under the running water until all the water is seeped through.
This may take up to 3-4 minutes per filter.
Repeat with other filter
Notes
Only use cold water; never use warm water, hot water, or soap to prime the elements.
It can take 3-4 minutes per filter. It takes awhile sometimes, so if you feel like you're doing something wrong, try to wait a little longer, and it may start seeping through correctly.
If after 3-4 minutes you don't notice any water seeping through, try to readjust the priming button or the water flow to see if that helps.