Starting groupbuys- Make the item, post an ic, and just roll with it
Get enough interest and start a gb post usually via google forms, but if its a large run, set up a website or get vendors, take money, order, wait, get everything, spend days packing.
If its keyset, ic, vendors, quotes, wait, stonks
In regards to keyboard manus, just go around finding whoever, china has a lot of quality ones just roaming around on alibaba and other chinese sites