In general MindNodes supported shortcuts should automatically be accessible via the Siri Shortcuts app.
Should this not be the case please follow these steps:
1. Open MindNode for iOS
2. Open the settings in MindNode (little gear icon, upper left corner)
3. Select Settings again
4. Shake your device and tap on 'Show Settings'
5. Now tap on 'Donate Siri Shortcuts':
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