Yes POP3 is disabled by default.
Start the service first (Start, Run Services.msc) - you cannot start it via Exchange System Manager.
Then check the POP3 Service under Exchange System Manager is started.
Open up TCP Port 110 on your firewall and forward this to your server and check on www.canyouseeme.org for port 110 - you should get a good result if the port is open and forwarded happily.