[Q] How to make updater-script?

hi DEV....
I want to make the updater-script for my update.zip.

how the script is correct. if I want to do this:
1. create a folder "backupApp" in sdcard
2. copy "/system/app/browser.apk" to "sdcard/backupApp/browser.apk"
3. Delete "/system/app/browser.apk".

I want to uninstall browser.apk of the system.

thanks.