Connect your iPhone to the computer via USB. Enable "Sync with this iPhone over Wi-Fi" in iTunes or Finder.
Open AltStore on your phone, go to the "My Apps" tab, and tap the in the top-left corner. Grand Theft Auto- Vice City v1.6 IPA FOR iPHONE
Drag and drop the downloaded Grand Theft Auto: Vice City v1.6 IPA file into the tool interface. Connect your iPhone to the computer via USB