The video tutorial of this topic can be found here.
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Within the Augmented Reality and Place view:
Tap on the 3D model to select
Use one finger to move the 3D model
Rotate two fingers to rotate the selected 3D model
Learn how to scale your 3D model here
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Within the 3D view, the gestures are slightly different:
Use one finger to rotate your view of the 3D model
Pinch 2 fingers open or close to zoom in and out of the 3D model