A:
Your tablet should have a File Manager program already installed. It might be called MY FILES or something similar. Otherwise, you can download a File Manager ap from the Ap Store or Google Play.
In many of these aps, you select the files, select COPY or MOVE from a pop-up menu, then browse to the destination folder and select PASTE.
You can often also use your Photo Gallery ap to MOVE the files. Select the files and select MOVE from a pop-up menu. The ap should prompt you to select the destination folder.
An alternative is to connect the tablet to your computer and connect the memory card to you computer as well through a card adapter, then use (in Windows for example) Computer or Explorer to Drag&Drop the files from one device to another.
There are even more ways to transfer the files, e.g. send them to the Cloud, Facebook, Dropbox, etc., then pull them back down directly onto the SD card that is installed in the tablet..