Flashing CM13 on Galaxy Tab GT-P3100
Caution: I have rooted my device for the first time, I have no prior experience in rooting. Continue at your own risk.

I am not sure about the RAM part, but we can flash the custom ROM from the internal SD card too. The following link is for explains the installation process for Installing CM 10.1 on Galaxy Tab2, however, we can follow the same steps for GT-P3100:

https://www.droidviews.com/how-to-install-cyanogenmod-10-1-rom-on-samsung-galaxy-tab-2-7-0-and-tab-2-10-1/

I also followed the following youtube video and downloaded the zips for CM and Gapp from the link in the description:

https://www.youtube.com/watch?v=MYZUKqGPNcE

Also, I had an error while installing the Gapp(it got aborted). I fixed it using the default option in the menu. 

Finally, the device is working properly, there was no issue due to the error encountered during Gapp installation.