Super super simple.
This is the filter responsible for catching any liquid the compressor shoots out. Compressors have a tendency to accumulate water / oil and other nasties you want to keep out of your filter.
I use a Meissner CSPM0.2-222 - it's actually a 0.2um filter with 3/8" barbs. I picked mine up from Heyes but I had an inside kind of deal. I think Cole-Parmer is probably the best place to look. You just need a barb air filter with a 0.1-0.3ish micro rating and that is responsible for filtering the crap out of the air. They likely sell Whatman.
Then you need a ball valve with built-in check valve. I know GW Kent has these but I'm sure someone else does as well.
All of this is connecting with some nice stiff tubing - I believe mind is 3/8" Bevlex poly braid. And of course you'll need the fitting to connect it to the compressor - normal male compressor insert.
I'm not sure there's another picture I could post that would help but I'm certainly happy to provide any more detail you'd like.