Install qmk package for arch and set it up.
yay qmk
qmk setup
Steps to build keymap and flash it from arch.
qmk new-keymap -kb mechwild/obe/f401
Open the keymap.c file (location provided in the output of previous command). Change any maps that need to be changed. List of keycodes here
qmk compile -kb mechwild/obe/f401 -km obe_arch_401_multilayer
If successful, disconnect keeb, hold ESC key and connect again to put it in DFU mode Keeb should become unresponsive if it goes into DFU mode
qmk flash -kb mechwild/obe/f401 -km obe_arch_401_multilayer
If there are any success messages, then it's good to go. Disconnect keeb and reconnect, it should be working now.