Xbox360 game adding

so i just bought this Xbox dash freestyle 3 and it already have 63 games in this Ext. Hard drive
I just download GTA V and Just Dance 4 but IDK how to add more games.
I already add Just dance 4 into this ext.Drive but the Xbox can't deetect it
Do i need to do something first before adding it or there is an app to do this ?

no you dont. Purchase a disc and no need to install on hard drive

Or buy through the marketplace and nth else it'll just install on ur hard drive if you have the space. No need any programs

You could use a USB, but all the games have DMR so it wouldn't work unless you have a JTag xbox.

The external hard drive has to be in Xbox 360 format if it's a game you purchased.

If you go to System>Storage>Select The Hard drive

It then should ask if you want to format it so it works on the Xbox 360 and just do that.