Learned a lot, not completely satisfied with the turnout, but I'll have more ammo for the next build.
Nice!Nano V2 using ZMK firmware, BLE, and custom PCB made with ergogen, kicad, and purchased thru JLPCB. Going to print a case and learn the keyboard layout.
The layout looks Colemak-ish, so I'd expect the E to be the key labeled 5 on the right half.
Smaller keyboards like this use layers to reuse certain keys, rather than adding more. The idea is to minimize finger/hand/arm movement. Things like choosing a more efficient layout (QWERTY is actuality pretty bad in that regard), using home row mods (so the letter keys under your index fingers double as Shift when held, for example), and so on.
It takes some getting used to, but it actually quickly becomes second nature.