Please follow the steps to upgrade to Pro version of Xmind for Desktop.
1. Download Xmind for Desktop: https://www.xmind.app/download/
2. Launch Xmind for Desktop,
3. Create a mind map (Windows),
4. Click「Help」 > 「Sign In」,
5. Enter your Xmind ID/Email with Password and click 「Sign In」.
macOS:
Windows: