I just recently found out the importance of backing up the keystore file in Android Studio. I have two apps published using this computer. Both times I simply used "Generate APK" in Android Studio Build drop down. I would really appreciate some instructions on where exactly can I find the keystore file that Android Studio used to sign those apks with and what else do I need to do to be able to publish updates to my apps from PC's other than this one. Thank you.
Try to check the menu:
Build
-> Generate Signed APK
The path to the keystore would be displayed on the first line of the new window.
But if you don't remember the passwords then I have some bad news for you :-(