Click the Start Downloading button in the tool.
Once the Xmobile X3 reboots:
: Open the SP Flash Tool (or compatible feature phone flash tool).
To flash, you generally need the firmware file, the correct SPD driver, and the SPD Upgrade Tool.
Most Xmobile feature phones utilize the chipset, often the MT6261 . You will typically need the SP Flash Tool or Miracle Box for the installation.