Step 1: start a degree in chemical engineering. By about year 3 or 4 you should have enough knowledge to design something bad but functional. After that you learn how to make it less bad, but never good.

Your use of the word "fluid" is the challenge. Now we have to consider the phase (gas or liquid), any chemical hazards such as flammable gases, pressures, compatible and incompatible materials, if you need pumps or compressors.

Distance and height differential are very important. For instance, a stormwater pipe from your roof to the ground is easy; an oil pipeline that goes up mountains and down valleys is much harder to design.