if its because its a zip file then u can do this: download ZArchiver on ur phone and then download any zip or rar file then when its finished downloading go to ZArchiver and go to downloads then tap on the zip or rar file u downloaded and tap "Extract" then choose the destination u wanna extract the file in and tap the 2 arrow button on the bottom right corner then it will start extracting then when it extracts click on it and u should see the apk download have a good day (srry for yapping)