Go to Settings > Security and enable "Install from Unknown Sources" to allow the installation of third-party APKs.
Cross DJ 4 Decks APK Download for Android: The Ultimate Mobile Mixing Guide cross dj 4 decks apk download for android
Open the XAPK installer, select the Cross DJ file, and follow the on-screen instructions. Go to Settings > Security and enable "Install
Note: On budget phones, 4-deck mode may cause audio crackling or app crashes. select the Cross DJ file