Steps

1. Inspect eth0 and wlan0 by running ifconfig. See wlan0 is RUNNING and eth0 is not.
2. Edit /etc/netplan/*.yml to have the following:

network:
    version: 2
    ethernets:
      renderer: networkd
      eth0:
        dhcp4: true

1. Apply using sudo netplan apply
2. Inspect eth0 and wlan0: ifconfig. See eth0 is RUNNING and wlan0 is not.