First of all, you need to download official CyanogenMod 10 Android 4.1.2 Jelly Bean custom ROM. Click here to do so.
Connect your Galaxy Ace Plus S7500 to PC using the USB cable, and then transfer the downloaded file to the core of its SD card.
Shut down your device and enter it into the Recovery Mode. For this, press Volume Up, Home and Power buttons simultaneously.
Navigate to 'install update from external SDcard' choose zip from SDcard'.
Use Volume keys to go up or down through the available options. Highlight the file downloaded in the first step, and then finally, press power button to select this file.
Confirm the installation process, and let it complete. It will take a few minutes to get completed.
Go to recovery main menu by selecting the "Go Back" option and then select the 'reboot system now'.
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