Hi!
Look at
**broken link removed**
in the downloads section (page in russian, 4 pdfs - english)
BenQ M23 Cellular Engine Module Description ,
BenQ M23 AT Commands ,
RTC Backup Battery Circuit for M23 ,
M23_M23G Designguide Rev_01
Most valuable for me was AT commands pdf - I used PC's Br@y++ Terminal (https://bray.velenje.cx/avr/terminal - try googling if this link is old, you can use windows' hyperterminal instead) and my M23 module on evaluation board (Baiyi Technology) for learning some simple dial and SMS operations.
If you are novice in micros, you can download and try Bascom-AVR (demo version - more than enough for beginning) from https://www.mcselec.com .
It comes with a lots of examples in Samples folder.
There are application notes about bascom programming on www.mcselec.com