If you're new to custom mechanical keyboards, four things decide how your board looks, sounds and feels. Here's the short version.
The layout is the shape and key count. In CDkeys you'll see:
Bigger = more keys but more desk space. Start with 65% or 75% if you're unsure.
Switches sit under every key and decide the feel and sound.
Keycaps are the plastic caps you actually touch. Two things matter:
Any keycap set fits any MX-style switch, so pick what looks best.
The PCB decides connectivity and features. Look for:
The PCB has to match the case, so CDkeys filters compatible PCBs for you automatically.