Download and install the Plastic SCM Cloud Client.
Open the Plastic SCM Cloud Client and log in.
Join the Plastic Organization (this is different from your Unity organization) where the existing repository is located).
Select the workflow that fits your needs.
With this workflow, you can work with branching and merging. To check in your changes straight to your cloud repository, create your workspace using the centralized tab.
Gluon Workflow
This workflow tailored for artists allows you to pick the files you want to work on and check them back in without updating your whole workspace. To work inside the Unity Editor, make sure to configure Gluon to pull down all Unity project files required to open a Unity project.
Note: Unity will add the ability to join projects directly from the Unity Hub in a future version.
You can access the Plastic SCM window in the Unity Editor by selecting Window > Plastic SCM.