When you're finished with your design, you will export both a schematic and board file to email to your instructor. Your instructor will preview your files to look for mistakes.
Open your schematic.
Choose File > Export
Choose Eagle Compatible Schematic Files (sch).
Press Export and save to your desktop.
Open your PCB.
Choose File > Export
Choose Eagle Compatible Board Files (brd).
Press Export and save to your desktop.
Email these two files to your instructor (.sch .brd)
Along with:
Your partner name
The color you want for your circuit board.