1.) Open cmd.exe
2.) netsh wlan show profiles
The wifi profile names will be shown in the current priority order under the section "User profiles". Its important to note, that the section starts with "Profiles on interface INTERFACE", where INTERFACE is the interfacename. If you got multiple wifi interfaces, that section will reoccur with its own "User profiles" and priority list.
3.) To change the priority of one network, enter:
netsh wlan set profileorder name="WIFIPROFILE" interface="I" priority=NUMBER
You need to give the correct wifi name as WIFIPROFILE, the interface which uses said profile as I and the NUMBER for the priority, with 1 being the highest, i.e. should be used prefered. You can also define priorities lesser than 1.