The documentation states you need to deploy a ‘server’ that sends a downlink to the device when the first (empty) uplink packet is received. (Downlink should contain time stamp in a certain format)
The node-red example provided in the documentation will provide the required functionality.
However the firmware for these devices uses confirmed uplink for every transmission, if you do not set the interval to very infrequent uplinks you will be breaching the TTN fair access policy which allows for maximum of 10 confirmed uplinks per day. (Equals ten transmissions a day)
The confirmed uplinks are an issue anyway (even when ignoring the TTN fair access policy) because of scalability issues, it drastically reduces the number of nodes a gateway can support.