Hi Heinrich, Yes, you can use the learning license to practice and play around, however, I would recommend not using any models you plan to use commercially. Below are the terms to the learning license.

The licensing terms limit the usage of Tekla Structures Learning for non-productive use only.

Tekla Structures Learning configuration produces educational output:

• Building information models created or saved with Tekla Structures Learning are educational models.
• They are compatible with Tekla Structures Educational configuration, but they cannot be opened in commercial configurations of Tekla Structures.
• Drawings created or saved with Tekla Structures Learning display a watermark stamp inscribed with Tekla Structures Educational text.

​I hope this helps.