Download and install the fabric loader from https://fabricmc.net/use/
Download Fabric API from https://www.curseforge.com/minecraft/mc-mods/fabric-api/files. Place in mods folder. If no mods folder exists, create one in your Minecraft directory.
Download Flytre Lib from https://www.curseforge.com/minecraft/mc-mods/flytrelib/files. Place in mods folder.
Download Mechanix from https://www.curseforge.com/minecraft/mc-mods/mechanix/files. Place in mods folder.
Download Pipe from https://www.curseforge.com/minecraft/mc-mods/pipe/files. Place in mods folder.
To be clear, Mechanix requires FlytreLib and FabricAPI to run. All other mods are optional. Pipe was originally part of Mechanix but was then separated. It is highly recommended to install Pipe.