Please refer to the Galaxy Expand - Initial Configuration for details on how to set up DHCP on the Galaxy server card prior to installing FXS 16-port cards in either the Galaxy Expand or Galaxy Express chassis. The same document identifies how to idenitfy the IP address of the FXS 16-port card after it has been powered on within the chassis.
Begin by pointing you browser to the IP address identified in the previous section. The default username is admin. In most cases, the default password will be emetr0tel. Note that some older versions of FXS 16-port card firmware have a default password of admin.