get the Nostr App store first, i downloaded the APK for zap.store and then once i had their app store on my android phone, i downloaded Amber through that...

on the zap.store ... i believe you have to go to the github to get the apk, i think the download button didn't do anything....

That is the hardest part, trying to find the APK or get it downloaded, but once it's on your phone you call find what you need