Uh... the same way you did the fixed side maybe?
1. Created a new Component. Made sure it was Active.
2. Started a new Sketch, right on the main face of the fixed side.
3. Drew a long rectangle, and projected the shape of your three holes like this:
4. Stopped the Sketch and created a base Flange from it, with the three holes.
5. Flanged each of the three holes up 90-deg to make the hinge tabs like this:

6. Started a second Sketch down at the end and projected one of your existing hinge tabs and my flange, like this:

7. Extruded that profile all the way down with the Intersect option chosen, like this:
8. And finally, Grounded your stuff and Revolve Jointed my bit into place.