This article is in the Control section of the App.
In order to restrict access for certain team members for your organisation, go to the Control section of OpenSolar, click on Company and then Settings on the left hand sidebar.
From here, go to Project Access Control.
From here you will have two options:
If you choose Unrestricted, then all of the members in your organisation will able to see all projects.
If you choose Restricted, any team members which are Non-admins (find out about admins and non-admins here) will only be able to access projects that they are assigned to (find out about assigning here). Any other projects that they are not assigned to will not be visible to them if they are a non-admin, but will be visible to any team members that are Admins.
Note: When a team member creates a new project, they are assigned to it by default, but this can be changed by re-visiting the project page later.