If you have an environment that was created outside of a project, you can add it to a search project. An environment can be associated with only one project.
To attach the environment to a project:
On the Projects tab, go to Projects > Your Project > Environments.
Click Add Environment.
Select Add an Existing, Unassociated Environment.
If this option is grayed out, you have no unassociated environments.
Select the environment name.
Click Add.