Need advice on Arduino and SIM900A powering

Hello everyone.

I have a project which requires both Arduino and a GSM SIM900A module(which has a input voltage of 5V). From what i have found so far, the SIM900A module may draw current up to 2A which means i cannot power it using the 5V pin from Arduino and need to resort to another external power supply.

However i think it is a bit pointless to have 2 separate power supply for a single project so i hope that i can power both of them using a single power supply only and in the best case scenario, powering both of them using batteries to make my project portable(which seems unlikely).

At first i was thinking about using a 5V 2A DC adapter to power both the Arduino and the GSM device by connecting the adapter to my breadboard and distribute the power to Arduino through the 5V pin and to the GSM module. Then, i read that it is not advisable to supply voltage to Arduino through the 5V pin as it may damage the board.

Any suggestions or advices on how should i power my projects?

Thanks.

(I am a total beginner to electronics so i may ask some noob questions.)