This assumes you've already created a channel, which you can verify by displaying the channel.

Define a listener for the channel.

echo "define listener(LISTENER01) trptype(TCP) control(QMGR) port(1414)" | runmqsc MANAGER01

Start the listener.

echo "start listener(LISTENER01)" | runmqsc MANAGER01

You almost always also want to assign one or more users that have access to the channel so that you don't get error 2035 MQRC_NOT_AUTHORIZED when attempting to connect to MQ.