I have iphone 4 ios 6.1.3 and want to downgrade to ios6.1.2?

Videos or links would help a lot

So far, I haven't found anything that helps when it comes to downgrading… And I don't really see how you can downgrade… Its only one way.

The only way to "downgrade" is to restore using an old version's firmware. Download that firmware from the internet then restore the phone and point the restore to that firmware.