Can someone tell me how to disable DHCP on Transport WR44?

You can disable DHCP on any port.
Do not connect the device to your LAN or else WR44 will hand out IP address to other devices in your LAN.
Connect it directly to your computer and change the network settings of your PC by assigning IP address in the 192.168.1. network as the default IP address of WR44 is
you can open Digi Discovery Tool and discover the device.
Open the Web interface navigate to configuration> interfaces> DHCP server > DHCP sever N > uncheck the checkbox which says enable DHCP server on this interface.

You can also connect your PC to serial port of WR44 and issue few commands to disable DHCP on a particular port

connect to serial port
issue below commands

eth n dhcpcli on (n= 0/1/2/3 )
save all

eth 0 dhcpcli on will make the device dhcp client
to disable the DHCP server issue the below command

dhcp 0 ipmin !