Newbie/ Memory Management?

What version of Android is installed on your tablet? You can find out by going to menu>settings>about phone.

With Android 4.1 or later the memory model changed somewhat to provide more space for apps. Out of the box, they will always install to your internal memory. There are tweaks to get apps to install and run from an SD card, but I wouldn't recommend it unless you have a specific need. Apps by default will never install to an external SD card if you have an internal /sdcard partition.

To copy files to your sd card, a file manager will come in very hands. ES File Explorer or Astro are both popular.

As far as your permissions go, those app permissions apply only to the app in question, so if you aren't instructing it to delete something, it won't do it on it's own. Having the ability to read, write and delete files from an SD card is a common permission for file managers or camera apps, but if you have concerns, just let us know what the app is and we can take a look for you.

 

Apps for the most part won't use the sd card at all. It is supposed to be for file and media storage.