Im a student and I have been assigned the task of creating a logical network diagram for the following scenario

There are 2 buildings, the first is the head office and the second is the branch.

The data centre is in the head office, it contains domain controller, mail server, file server and a web server. it provides wired and wireless access to the staff.

the branch building is new and it does not have a network.

The two buildings must be connected using a VPN connection.

The branch building will not have any servers but just network devices that will provide the connectivity, the users in the branch building will be connected to the head office over the VPN.

I had created a diagram based on this scenario, but my teacher rejected it saying that it does not follow Cisco hierarchical Model and the servers were not placed correctly in the diagram.

I just wanted some help in this matter so that I Can create my network diagram correctly.

If anyone could upload a picture of how the logical diagram should be for this scenario will be helpful, any other resources would also be great.