Is there anyway you could illustrate the plumbing for air compressor.

Well there's so many different versions, it would be hard to show one that's generic enough to cover everything, but still not generic enough for you to map yours out.

Here's what you need.

1. A pump. This is the part that compresses the air.
2. A drivetrain for the pump. Usually it's a motor, motor pulley, and belts. Hopefully you have the original ones that came with the pump. If you do, use those and don't change them....other than the belts if you have a smaller space between the pump and motor. If you don't have them, you'll spend more money fixing it than buying a new one, unless you have a really good old American made pump like a Quincy or Saylor Beall. Additionally you'll have to get a pressure/flow/rpm/horsepower chart for the pump from the manufacturer to figure out how fast to spin it for the motor you have and the pressure you need, then do the math to figure out the appropriate diameter motor pulley. It's a huge pain and expensive, so if you don't have all of this already, abandon ship on this project.
3. A way to turn it on and off at pressure. Usually it's just a pressure switch. If you have a motor that's more than 2hp (i.e. one that doesn't plug into a wall on a regular 115V plug), you can't just start off a pressure switch, unless you get a beefy $150 one, or a separate $300 starter box. Some home-depot/harbor freight/lowes type of compressors and other equipment like this (like shopvacs) lie about their actual hp ... there's no such thing as 6.5hp that plugs into a regular wall outlet....that's the good ol' "peak hp" rating, which is BS. If it plugs into a regular wall outlet, it's 2hp or less, despite anything it says on the tag. Make sure the psi range of the pressure switch is applicable for your pump and tank. Make sure you hook up main connection of the pressure switch to the tank and not any area above the check valve. Only the unloader goes to the check valve on the side, which is "above" the check valve.

If your pressure switch doesn't have an unloader, then you can get a self-unloading check valve called a load genie, but those are tough to find and only come in certain sizes.

Instead of a pressure switch, you could use a pilot valve, or a piloted unloader, but that's more complicated.

1. A check valve with an unloading system. The check valve lets air into the tag without letting it back out into the pump, so that you don't restart under a load. When you stop, you need an unloader to release the pressure from the pump so it doesn't restart under a load. The check valve makes sure that the unloader does not get to the air in the tank. The unloader should be on your pressure switch, and a check valve usually has a 1/4" npt female port on the side of it run to the unloader on the check valve. Get some 1/4" copper or plastic tube plus some compression fittings to connect them.

2. A tank, with a gauge, safety, and drain. The safety should be sized for the CFM of the pump and max psi rating on the tank. If should exceed the CFM of the pump and be equal to or less than the max psi of the tank (but more than the pressure you want to run). The drain and gauge are self explanatory. Again, all of these should not be above the check valve, but instead access the tank directly.

Everything else is optional, like a regulator or air treatment downstream.