Is it possible to connect a USB Wi-Fi adapter to this RouterBOARD model to share internet, and how would I configure it?
Thank you very much
Doubtful.
You can check this page but I do not see a lot wifi related in there.
If not particularly worried about throughput your best bet is to get a cheap AP. The haplite series $24 provides 2.4ghz connectivity.
if you had bought the hap axS, that comes with wifi.