Hi @Josie Li and @Hyounwoo Sung ,
Thanks for your patience. The sample code is being cleaned up and should be available soon but we currently don't have an ETA of when it will be ready. The APIs that you are pointing to are from the demo code and are not specific ACS APIS. You can assign a bot token/identity using the regular Auth APIs themselves.
Here is a doc that explains the access tokens: https://video2.skills-academy.com/en-us/azure/communication-services/quickstarts/access-tokens?pivots=programming-language-csharp
Hope that helps.
-Grace