To get started, get some M590 modules. I remcommend getting several modules becuase sometimes a used module is less than perfect and may have poor signal quality or some other problem.    Build up the M590 PCB and connect to it a USB TTL serial data module set to 3.3V. Power the module off an 18650 cell.  Choose a nice Terminal program. I like to use Terminal v1.9b by Bray. 

Some tips: 

The M590 will most likely be trying to communicate with the last-used settings, 115 Kbs etc.  So one of the first things you ought to do is change the default bit rate to something easier to work with 9,600 bps.  

There's a lot of pages on the Net about getting up and running

 You might need to try another module if it's not working too well.   Send a SMS (there's plenty of pages on the web about how).   You'll likely get bored quickly with SMS so now let's have some fun 

Look for the file on this page with the list of undocumented commands.  

A good one to start with is :

AT+CGED

Now call the number of the SIM card.

You should get something like this: 

RING

+CGED: 

Service Cell: 

MCC:214, MNC:  7, LAC:0dae, CI:3107, BSIC:00,

Equivalent PLMNs:

MCC:214, MNC:  7

Arfcn:00016, RxLevServ:020, RfChannels:000, ArÖ¹}‘•‘é068,

RxLevFull:013, RxLevSub:029, RxQualFull:006, RxQualSub:000, GSM Ciphering:ON, GPRS Ciphering Algorithm: GEA0,

ms_txpwr:005, rx_acc_min:255, cbq:ff, cba:ff, c2_valid:False, cr_offset:255,

tmp_offset:255, penalty_t:ff, c1:-32768, c2:-32768, ch_type:02, ch_mode:0b,

txpwr:006, dtx_used:False, drx_used:True, t3212:00255, acc:ffff, t_adv:004, bs_pa_mfrms:255,

dsc:255, rll:032,

amr_acs:0, amr_cod_ul:0 amr_cod_dl:2 amr_c_i:126,

BEP GMSK: mean_bep_gmsk:255, cv_bep_gmsk:255, BEP 8PSK: mean_bep_8psk:255, cv_bep_8psk:255,

Neighbour Cell 1:
MCC: -1, MNC:255, LAC:ffff, CI:ffff, BSIC:0b, Arfcn:00014, RxLev:015, 
C1_nc:32768, C2_nc:32768,