[SOLVED] Hidden project

Before I tell you how achievable, it is just a small point of detail : On the detail page of a project, in the treatment section, you have the option to check the box "under construction". So the project will not appear in the timesheet table and no email or alert about this project will be generated automatically.
Anyway, PROJEQTOR allows a user (usually the person who has an administrator profile) to define the rights of each to create, to view and / or to modify a project depending on a given profil.
The flexibility of the software also makes it possible to modify the rights of the resource on a particular project by simply modifying the profile of the resource during the allocation to this project.
For example it can pass rights given to a project manager to those of an administrator on this project, or vice versa. This is valid for all the panel of profiles.
To define your rights the first time or to revise them GO to "access rights". IF ok and depending on them, then you just have, perhaps, to switch them on allocation of the resource to the project aimed.

Just create project, without allocate any resource : only admin can see it.
Allocate tems members (possible throught team screen) : they will see the project (and noone else except admin)

No,
Give them the reader+ access right (then they can see all projects) and allocated them on specific projects with a profile having "manager" access right (then they'll be able to update these projects)