Hi Jai,
To install CommCareODK on an Android, you have to install first the CommCareODK client from the market, and then your application that you built in HQ.
It sounds like you've installed the CommCareODK client from the market just fine, but are having trouble installing your application.
If you go to your project on HQ, click on "Applications" section. You will see a link on the top right to the "Release Manager". Here you can deploy existing builds - or if you don't have a build yet, click "Make a build" to create one. For a detailed tutorial on how to create and deploy an application, please see our beginner's tutorial:
https://confluence.dimagi.com/display/commcarepublic/Beginner+Tutorial
Let us know if you're still having issues. We'll update our documentation so it's more clear going forward!
Thanks,
Amelia