First, ensure that the computer/sbc has WI-FI parts.
install wpa_supplicant, edit /etc/wpa_supplicant/wpa_supplicant.conf, with ssid & psk.
Then run wpa_supplicant -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf & to connect to the named ssid.
ip a add ipv4-addr
ip r add default gw