how do i download games on my ipod touch

Whixh ipod do you have?

Is it updated to the latest available version?

You may simply have an ipod that is too old to get the latest updates.

Identifying iPod models - Apple Support

To update

The Settings>General>Software Update comes with iOS 5 and later.

Connect the iPod to your computer and update via iTunes as far as your iPod model allows

iOS: How to update your iPhone, iPad, or iPod touch

A 1G iPod can go to iOS 2.2 via iTunes and iOS 3.1.3 via

Purchasing iOS 3.1 Software Update for iPod touch (1st generation)

https://buy.itunes.apple.com/WebObjects/MZFinance.woa/wa/touchLegacyLandingPage

- A 2G to 4.2.1. Requires iTunes version 10 or higher. If a Mac it requires OSX 10.5.8 or later.

- A 3G to 5.1.1 Requires iTunes version 10.5 or later

- A 4G to 6.1.6 Requires iTunes version 10.7 or later. For a Mac, that requires a Mac with OSX 10.6.8 or later

- A 5G to iOS 7.1.1 Requires iTunes 11.1 or later if you update via iTunes

Identifying iPod models

To more easily find compatible apps:

iOSSearch - search the iTunes store for compatible apps.

Apple Club - filter apps by iOS version.

Starting when iOS 7 was released, Apple now allows downloading the last compatible version of some apps (iOS 4.2.1 and later only)

App Store: Downloading Older Versions of Apps on iOS - Apple Club

App Store: Install the latest compatible version of an app

You first have to download the non-compatible version on your computer. Then when you try to purchase the version on your iPod you will be offered a compatible version if one exists.