An adjustable wrench is a steel wrench tool with a head that can be adapted to fit a wide variety of nuts and bolts. With pneumatic fittings, it's used to loosen and tighten the compression nuts that hold the pipe fittings together. When you're tightening the pneumatic fittings, make sure that the compression nut is tight, but not overly tight. Over-tightening the compression bolt can cause the pipe to break or create a leak in the fitting.
Plumbers grease is a thick oil-based lubricant melted from animal fat and used to keep the compression fittings slick. When changing the compression fittings you want to apply the a good amount of the plumbers grease to both male threads of the compression seat without letting the grease bunch up. Applying too much grease could cause the compression seat or the entire compression fitting to malfunction.
A nylon acid brush is a disposable brush used for applying glue, lubrication or acid coatings. Generally they are produced for one-time use. They should be used to apply the plumbers grease to the compression fittings. They come in a variety of different sizes; however, you should use a 3/4" brush because it's made precisely for applying lubricants to small machine parts such as the compression fittings.