Never built a keyboard before? I hadn't, either. I read through the ErgoDox assembly guide once or twice, but what really made me confident that I could do this was watching this build video several times:

The point of building your own keyboard is to make it yours. Your colors, your feels. Never clacked a mechanical switch before? Get a switch tester. Try someone else's keyboard if you can.

These are the things you must decide:

• diodes - SMD or through-hole?
• switches - do you want tactility or a smooth ride?
• caps - uniform? sculpted? ABS? PBT?
• case - is it okay if people see your solder joints?
• cords - these make your keeb 20-50% coolef

Time to order parts. Ideally, you should at least have solved the SMD/THT diode question. You can get kits, you can get component-only kits, or you can gather everything yourself. Make sure you get the right TRRS jacks, though.

If you're gonna have the boards fabbed and are comfortable with gerbers, this is the time to add your own stuff to the silkscreen, move the thumb cluster closer to the rest of the keys, change the ErgoDox logo to literally anything other than Comic Sans, et cetera.

The design supports SMD and THT diodes. Make sure you know which way they should go on both halves! The board is the same for both hands, just flipped. This means the diodes get flipped.

Did you flip the boards over and swap them? The diodes should be on the bottom now. Everything else goes on the other side.

The ErgoDox (the one I built, anyway) has the Teensy set perpendicularly to the case, so the mini-USB has to be extended from the Teensy to the edge with an exposed male that gets wired to the board.

If you wire up your own extender from a kit, verify the wiring before you plug it in to a computer. It might be easier to sacrifice a mini-USB cable, but you will have to cut into the plastic housing and free the skeleton and wires.

This is where it starts to come together. The switches must be soldered to the board with the acrylic plate layer in between them. Solder a few switches in the corners and make sure everything is lined up before doing all 76 of them.

You might want to see if it will keyboard before you bother to put the case all the way together. Flash whatever firmware you want that will work on a Teensy. I used QMK, but TMK will work, too.