K&N's kit is called the FilterCharger, but as stated, you can buy the cleaner and oil separately, or use other similar aftermarket products.

The actual cleaning is pretty simple, but it does take a little time...... I usually do it when I know I won't be riding that evening just because of it.  Usually when I'm starting an oil change, so it has maximum time to dry.

Step 1 - setup......   Find a sink or tub that you don't mind getting dirty - this can be a messy job...  I also like to have access to a furnace outlet, as it gives a nice gentle warm airflow to help dry the gauze when it's time.... but this isn't really necessary.

Step 2 - Cleaning..... The first thing is to soak the filter with the soap and let it sit a while.  The soap is formulated to dissolve the oil, so you can rinse out the dirt from the filter.  If there's lots of bugs, etc, you can shake or bang them out of the filter - but don't get too panicky here - or you can damage the filter.  You'll want to do this over your sink, as it's FILTHY when it drips..... but it will wash away with water.

Step 3 - Rinsing..... There is one thing that is MOST IMPORTANT here - ALWAYS let the water flow from the INSIDE towards the OUTSIDE of the filter - the opposite direction of the normal airflow. This prevents bugs, dirt and other crud from getting on the wrong side of the filter where they may dislodge - and may get into and damage your engine. 

Step 4 - Repeat if necessary..... I've found that most times I have to repeat the soap soak and rinse to get as much of the dirt out as possible.  Eventually, the gauze will stain and not look so pristine as it did originally. It doesn't hurt the filter or it's performance, it just looks a bit dirtier than new.

Step 5 - Dry......  Do NOT use pressurized air - it WILL damage the gauze (It tears easily, that's part of why it's trapped between 2 mesh nets). If you can set it in the warm sun for a few hours, or overnight - great. Personally, I sit mine on a furnace register where the warm gentle airflow will dry it nicely overnight.  But it NEEDS to be dry for the next step.....

Step 6 - Oil.....  This is why K&N oil is red.... so you can see WHERE you've sprayed the stuff. You want it relatively even, but don't go overboard, or you'll have oil dripping all over your bike.  Personally, I spray a light coat both inside and outside of the filter. I can't ensure I get oil between ALL the pleats, but if I get it on the top of each pleat (both inside and out), it WILL migrate. I try to aim into the pleats where I can, but some of them are pretty close together.

Step 7 - Reinstall.... You're supposed to let the filter sit for a while to let the oil migrate, then you wipe off the drippings, and install it..... then RIDE!

Really - except for the drying time, it should only take you 1/2 hour to do it....  of course cleaning up the sink will take another 1/2 hour...... LOL (mine gets pretty filthy)

In a pinch, K&N says you can knock out the worst of the dirt, and just spray a little oil on the filter, and you're good to go for a few thousand more miles..... It's not as good as a proper cleaning, but it will help - and it still flows more air than ANY paper filter can, and still traps more dirt.

As Shaker mentioned in Step #6, I also spray a light coat of K&N oil on both sides of filter.
Step #7 reinstall filter on bike. I let mine sit for at least 6-8hrs before starting or riding. I also lay a rag under the filter just in case excess oil drips down.
Awesome Tutorial Norm

Don't overthink this.  It's a filter.  You can't clean them too soon or too often. 

Whilst where on the filter topic, here’s a before & after.

K & N Recharge kit for me easy...

Actually, you can. From the K&N FAQ: "cleaning a filter too often will shorten its serviceable life expectancy." K&N considers their filters to be a "lifetime" filter. However, if you decided to clean the filter after every ride you would very quickly wear the thing out.

That's ridiculous.  Unless you are using a wire brush to scrub the filter, there is no way you are going to wear a filter out simply by rinsing it with a mild solvent, and re-oiling.