Hello,
You are correct, and you did not receive the texture files for the Twinmotion scene, which causes things to appear white and without textures. You will need your superior to send you the Twinmotion file by using the Resource Collector in the Edit menu of Twinmotion. This will package the .tm file with a maps folder that contains all of the scene's textures. By selecting the Compress option in the Resource Collecotr, Twinmotion will create a .zip file with all of the necessary files for the Twinmotion scene that can be easily shared and should fix this issue.
Best,
Raghib