For general navigation, use the arrows on the keyboard and the mouse "click" to enter any room or video.
Frequently asked questions VRtube-Virtual
Some mobile phones have problems rendering textures in 3D environments. Phones with Adreno 300 series GPUs are notoriously problematic in this regard. The minimum available memory of the handset should be 2GB. Make sure you don't have any applications open that are consuming memory.