Only registered WebCEO users can see the projects shared to them. Thus, your colleague needs to register an account at https://online.webceo.com using the email address that you shared the project to. Once they sign in with their registration email to our system, they will find the project you shared in their teamwork area.
Note that a shared project passes the functionality available in your WebCEO service plan to the user it is shared to, but that applies to the shared project only. The Free Trial user will also be able to create two free projects of their own with the limits of their service plan (Free Trial). They should know that they will not be able to share these free projects with you.