connecting and powering up a 9v gsm module..help

i have an arduino uno and a gsm module
i dpnt understand the rx,tx pins of gsm module as it is not marked as rx and tx anywhere...

and thus module accepts only 9v. so how to power it up ? anyother options other than battery..and ther is only 2 pins available.. no adapter port.. it is better for me to connect it using usb/adapter...
please help me

pls, post a link to your gsm module
how can we help if we don't know which module you're talking about ?

https://postimg.org/image/4di0eqdgh/

this is the module... simcom sim900a

and i have an adapter with output from 3v-12v..
also it has an option to choose polarity.. so what voltage should use and polarity...

i need to conect gsm to arduino.. arduino is powered using usb cablr.. can i use vin pin of arduino to power gsm which need 9v? if yes, i can only connect one pin right? but on gsm i jave 2 pins(if connected using battery,i can use both pins). so if i conect vin to +pina what should i conect to next pin?

no, you cannot use vin pin to power your GSM which is powered via USB (you'd get only 5V) - Vin pin allows you to power the arduino from an external power source(or to acces the external voltage if powered via the power jack).
So, You could use it for that if you powered the arduino via the power jack, you'd get the same voltage as in the power jack

if your GSM needs 9V, then you could use your external adapter at... 9V to power it and the arduino (via Vin) . You'll have to connect the arduino GND and the GSM module GND together .

have a look here

without more details about your GSM module (technical specs, documentation......, the photograph is almost useless to me) , I'm afraid I can't be very helpful