You will need to know the encapsulation and parameters for the T1 from the provider. Assuming ppp, something like this should work:
bridge 1 protocol ieee
!
interface t1 0/1
description T-1 from provider
tdm-group 1 timeslots 1-24 speed 64
no shutdown
!
interface ppp 1
no ip address
no shutdown
cross-connect 1 t1 0/1 1 ppp 1
bridge-group 1
!
!
interface eth 0/1
description Ethernet to Sonicwall
no ip address
no shutdown
bridge-group 1
Note that you won't be able to administer the device other than via the console unless you configure IRB and assign an IP from the range going to the Sonicwall to the T1. A simple bridge won't need a lot of configuration but having access to the device for troubleshooting can be handy.
If this T1 is an Internet T1, then the usual situation is to have the 3200 act as a router and not a bridge. The provider will typically assign a /30 to the T1 itself and a separate subnet for use by the equipment on-site. There are other options regarding the T1 itself that may need tweaks, such as if it uses a different encapsulation such as HDLC or frame-relay, if the line-coding or framing is not standard, which side provides clocking, and if it is sub-rate with fewer than 24 channels in use. It would be a good idea to get all of the specifics of the T1 from the provider, both layer 2 and layer 3.
