You really can't anymore. The highest ios for an iPod 2 is ios 4.2.1 and most apps today require ios 4.3, 5, or 6 to be downloaded. my iPod 2's speaker broke just from using it and it sits in a drawer now cuz I can't get apps and videos won't load.
Oh, and this is an iPod Touch 1st Generation. I can tell by how to metal is molded around the front. Does the wifi antenna take up a corner of the back or does it look like a stretched circle? If t is a first, the highest ios it can get is ios 3.1.3, so good luck finding any app that'll be compatible with it