First time App help :)

Hello fellow Android developers,

I am hoping someone can help me. I have built an App that I am planning to launch in he Google play store. As I am sure you will guess from my question this is my first App! I have done everything correctly so far and I have my merchant account setup and from a google perspective I am ready to go. I have a question though.

Some background first:

1) I am running Juno version 4.2.1 on Mac version 10.9.4
2) The App that has been built seems runs fine on test Android devices that are connected to my dev Mac
3) I have run the App on other test devices and it is running fine as well
4) I should say that the App itself is a very simple tool with a limited UI and limited user interaction

KeyStore:

When we are building the APK within Juno we are asked to set a master password. Can you please tell me what this password is for, how important it is and does it have to be extremely strong. Will we be the only people with the password or do we have to share with google.

‘Get License Key’

During the upload process When I click on this link it takes me to the ‘Licensing and In-App Billing’ section within ‘Services and APIs’ . What is this license key, what is it used for? Do I have to incorporate this into my App during the APK build process on Juno? What happens if I do not use one??

‘Upload your first APK to Production’

When we try to upload our first APK we get the following message:

You uploaded an APK that is not zip aligned. You will need to run a zip align tool on your APK and upload it again. Does anyone know what this means and how do I fix it?

Also, any other advice on launching my App would be great. This is my first app and the whole process seems really confusing. Do any of you have a pre launch check list?

I am sure some of you will see that I have uploaded this question on a couple of forums. sorry if you have had to read it twice!

Thanks Guys, Amelia ☺