Here’s the fix for not having sound on your TensorBook:
wget https://s3-us-west-1.amazonaws.com/lambda-labs-get/oem-audio-hda-daily-dkms_0.201804250316_ubuntu17.10.1_all.deb
sudo dpkg -i oem-audio-hda-daily-dkms_0.201804250316_ubuntu17.10.1_all.deb
sudo reboot
This should fix the audio for your TensorBook!