PCBgogo

Hi
When you talk about coatings / electronics / clean you immediately get into all sorts of corner cases. "No clean" flux is not no clean when you use a coating. Parts that use coatings in there construction may / may not be compatible with your coating process. Anything that as ever been near a silicone based mould release is not likely to work with a coating process. Some of this can be corrected with a cleaning process, some only by buying a different part. 
Cleaning used to be real easy. You grab XXXXX (now banned) and slap the part in a vapor degreaser. All the bad stuff winds up in the sludge in the bottom of the tank. You toss the tank full of sludge in the local waterway every so often (no not really, you send it off to the reclamation company). These days cleaning is a closed loop system and not at all cheap. What you use depends a lot on who you buy your system from.
After you get the boards clean, you need to get them dry. A board that bubbles up in the hot summer heat ... not at all good. The bottom line is that you need a bake at > 125C. Again your parts will dictate how long a bake. A day may be enough for some. A week may not be enough for others. Once the parts come out of bake, you need to coat them fairly soon. If you don't they will soak up moisture from the air. How soon? Again that depends on your parts. 
Doing the coating is pretty simple. Anything worth using is a two part mix. It's got a dye in it. You spray it in a spray booth with all the vents and protection. The stuff has a pot life after you mix it. You have to get absolutely everything clean before any of it dries on any of your gear. There is a cure process for the stuff. Heat is a pretty typical way to accelerate the process. 
If you really care about the result, plan on running everything through twice. Yes you need to pick a material that will work with that sort of process. You need that anyway, you *will* have voids. After the two coats, you run them past the black light and check for the nice glow on all the surfaces. Any that don't glow get re-coated. 
Fun stuff. 
Now you have aboard that is an absolute horror to do any sort of work on. It's not humidity proof. It simply is more immune to dirt / moisture / crud than it would be without the coating. That helps protect the parts. ... errr ... except that it really was designed for leaded parts. With SMT stuff, you trap gunk under the parts. With SMT, if the coating shrinks, you can tear the parts off the board.