How can I better model the relationships in this project? I'm developing an internal tool (as an intern). We deal with a lot of hardware, which is all custom and managers have a hard time knowing who is developing on what machine. 
The three main things to track for this project will be Hardware, Projects and the Employees. I'm struggling with how to deal with the managers.

I was struggling with databases and of course I have to design one in my first internship. Any and all suggestions are greatly appreciated.

Here is my current ERD:



Here is an excerpt from the design document for context:


  Tool Features
  
  
  Track gaming hardware:
  Sort or search by serial no, vendor, platform, type.
  Track project pool:
  See employees and VLT’s assigned by project. Emails are directly in the web >page.
  Track lab hardware:
  Sort or search by serial no, vendor platform and type.
I am still learning myself so you might not agree with everything I say.

In my business we have 'projects' that last for a certain amount of time and have staff assigned to them.

I would give your Employees a 'default role' eg Manager, Technician whatever. Then when they are added onto a project this role will be used by default in a drop-down menu unless you choose otherwise. This role may affect their pay rate for each project also.

If you really wanted to impress them you could make an application in Visual Basic for creating and updating the tables, you can do this for free I believe.