How to connect Network drive to T-Mobile Internet

Hola,

I just set up my T-Mobile internet, and am trying to transfer my networked devices. In particular, I have a network drive (personal cloud drive) that used to be connected to my wireless router (on my old network) via ethernet cable. I plugged in the drive into my T-Mobile gateway, but I cannot connect to it. I appreciate instructions on how to do this. Thank you in advance.

Peter