You need to install all 4 of the main packages if it's your first time, the update one is only for returning players.
This is what you do with each installer:
usually you install package -> open it -> press install inside it and wait for it to complete -> close app -> (optional - saves space) remove package app -> repeat with other packages -> install main apk and run the game
So yes you can delete the the package apps after installing their assets although you will then have to redownload them if you failed to install them correctly