FX30-3G Cellular Setup Instructions from existing SIM card

Could someone give me or direct me to a list of instructions to set up a cellular connection on the FX30? I personally have little experience with cellular.
I recently bought a FX30 3G (PN:1103214) and updated it to a recent version:

Firmware Version: SWI9X15Y_07.14.01.00 595652d jenkins 2018/10/26 08:34:29
Bootloader Version: SWI9X15Y_07.14.01.00 595652d jenkins 2018/10/26 08:48:35
Linux Version: 3.14.29ltsi-yocto-standard #2 PREEMPT Mon May 4 20:19:23 UTC 2020
FX30 Version: R17.0.1.007
Legato: 18.06.5.e4479a6a_4d846734b15dea928031af763d2d138c

I attached a 4G-capable antenna (what frequency bands do I need?), inserted an active TMobile SIM card, and entered what I think is the appropriate APN. However, “cm data” returns “Connected: no”, and the User Guide doesn’t include a good step-by-step of how to connect to the cellular service.

Here is my device info, following commands from a similar post:

at+cmee=1
OK
ati
Manufacturer: Sierra Wireless, Incorporated
Model: FX30
Revision: SWI9X15Y_07.14.01.00 595652d jenkins 2018/10/26 08:34:29
MEID: 35398408045638
ESN: 12804028728, 803D7938
IMEI: 353984080456385
IMEI SV: 48
FSN: LL820701510310
+GCAP: +CGSM,+FCLASS,+DS
OK
at+cpin?
+CPIN: READY
OK
at+cimi?
234500021915738
OK
at!gstatus?
!GSTATUS:
Current Time: 68325 Temperature: 25
Bootup Time: 0 Mode: ONLINE
System mode: GSM PS state: Not attached
GSM band: PCS1900
GSM channel: 671
GMM (PS) state: DEREGISTERED LIMITED SERVICE
MM (CS) state: IDLE LIMITED SERVICE
Serving Cell: 760 (GSM 1900 )
RX level (dBm):-96.1250 LAC: 016F (367)
GPRS State: GPRS IDLE Cell ID: 00006339 (25401)
IMS Reg State: UNKNOWN IMS Mode: Not Support
IMS Srv State: UNKNOWN SMS,UNKNOWN VoIP
OK
at+cops?
+COPS: 0,0,“Limited Service”,0
OK
at+cops=?
+COPS: (3,“T-Mobile”,“T-Mobile”,“310260”,0),(0,1,2,3,4),(0,1,2)
OK
at+cgdcont?
+CGDCONT: 1,“IP”,“epc.tmobile.com”,“0.0.0.0”,0,0
OK
at!pcinfo?
State: Online
LPM force flags - W_DISABLE:0, User:0, Temp:0, Volt:0, BIOS:0, GOBIIM:0
W_DISABLE: 0
Poweroff mode: 0
LPM Persistent: 0
OK

AT!GSTATUS shows it is in GSM mode.

Does TMO still have GSM/3G network?