As of version 1.12.0, the Autoware.Ai repositories were moved to Gitlab. Some documentation can be found on the wiki and more is available in the quickstart demo. Unfortunately, the specific manuals that you link to have not been updated since they were originally released. Autoware.Ai is a community-developed project so merge requests are always welcome!
Please also be aware that a newer project based on ROS 2 is actively being developed by The Autoware Foundation called Autoware.Auto. This project has significantlybetter documentation available at https://autowarefoundation.gitlab.io/.... However, it has not yet reached feature parity with Autoware.Ai.