Update:
If this answer seems out of place, the original question was "How do i Dulplicate keyframes?"
Probably the easiest way is to the Dope Sheet editor. There are several ways to get there:
- Click the icon on the bottom left corner of the 3D view and select Dope Sheet
- Click on the dropdown that says Default on the Info bar, and select Animation. (Or press CtrlLeft Arrow twice)
This will take you to the Animation layout, with a 3D view, Graph editor, and Dope sheet.
From the Dope sheet or the Graph editor, select keyframes, and press ShiftD to duplicate.