How to restrict access / grant CSM Configurable Workspace access to specific users

[ThunderDev]

How do you restrict access / grant CSM Configurable Workspace access for a specific set of users?

[Mallidi Suma]

Are you not able to see the UI builder in the left application navigator? 

Application Navigator -> UI Builder -> Under Experiences -> select the CSM Configurable workspace.

[ThunderDev]

Going to  UI Builder -> Under Experiences -> select the CSM Configurable workspace takes me directly to the UI Builder for CSM Configurable workspace.