Well a "Factory Reset" is usually tried to try and keep your data, where as a "Hard Reset" is to wipe everything and start over. So if you are OK with the total wipe, the instructions are below. However, if the tablet was perhaps rooted, then none of this will work as it only works on a normal (unrooted) device. In that case you would have to unroot the device first.
NOTE: Doing this will clear 'all' the data on your tablet, so it is suggested you not choose this option unless you have to, or aren't worried about losing anything on the device.
Be sure you back up any data you want to keep, to a computer or cloud account, before doing the reset.
To "Hard Reset" the tablet...
1. Make sure that the tablet is actually powered off.
2...