First start with updating and upgrading your OS => post
The use the following commands:
:-$ connmanctl
connmanctl> technologies
connmanctl> enable wifi
Likely it will say “Error wifi: Already enabled”
connmanctl> scan wifi
connmanctl> agent on
connmanctl> services
A list with available WiFi Networks will appear.
Use connect with the long string to the right of the network you’re trying to connect to – for example
connmanctl> connect wifi_………managed_psk
Use the tab to autocomplete, wifi_[TAB]