The PiTop comes in the box with the chassis to house the custom PCB, Raspberry Pi, Keyboard and Trackpad, as well as all of the cables. Once you've unboxed your PiTop, you just need to obtain a 2nd or 3rd generation Raspberry Pi, and you're all good to go.
The base of the PiTop comes out of the box seperated from the keyboard and screen.The needed cables and screws are stored in seperate bags and the PiTop includes one extra of each screw, should you lose one.
Once you've prepped everything you need (Your Pi, your chassis, screws, and cables ), you can begin building the PiTop. To start, you'll want to install four brass spacers and bolts onto both the Pi and the custom PCB, a miniature socket wrench may be helpful, but it can be done without one as well.
After you've installed the spacers, you'll want to prep the chassis for installation by removing the magnetic rails from the underside of the chassis. While focused on the chassis, you'll want to slide the screen and lid into the hinges on the base and then tighten it with the screws at the bottom of each hinge.
Following the attachment of the screen and lid, you'll need eight of the silver spacers so you can install the custom PCB and Raspberry Pi onto the rails, starting with the PCB, you'll place it on the left side of the rail system and align the pins with the battery slots in the aluminum base. If properly plugged in, the brass spacers will begin to show on the underside of the rails, here you will use the silver spacers to screw in the spacers using a provided allen wrench.
You will repeat the above process with the Raspberry Pi, without the process of aligning the pins. Move the Pi over to the right-hand side of the rail system, but not so far as to obstruct the USB ports (as you will need them later for the keyboard). Now you should connect the Pi with the PCB using the provided HDMI cable, Ribbon Cable (which should be routed through the provided cable management), and the USB cord for powering the Pi.
After wiring the Pi with the PCB, you should prep the keyboard for installation and wire the power button connector to the PCB, while wiring the Keyboard connector to the bottom left USB port on the Pi.
Upon connecting all of the wires, slide in your acrylic PiTop base, and boot it up. Congratulations, you've finished a PiTop!