How would I go about creating this curved mass?

[ctough]

[georgehobel]

I would create that as an extrusion. 

1.  starting with 3 new reference planes that center on each window and perpendicular to the window.  

2.  create an extrusion that is basically a rectangular block that sits under the window.

3.  create a series of three voids from each of the three reference planes I created earlier.  each void would have the profile to match your mass.  each void would cut the extrusion in its own path.. 

4.  done...

[barthbradley]

In-Place Model Revolve or In-Place Mass. 

[constantin.stroescu · Accepted solution]

you can do it by using Mass > Extrusion with Profiles , then scale the Profiles as shown in my screencast:

https://knowledge.autodesk.com/community/screencast/8a63ff46-8313-45b2-b80b-34182cd65b58

[barthbradley]

what took you so long, @constantin.stroescu?  

...he, he. just teasing you. 

[constantin.stroescu]

I took a nap....

joking...

[ctough]

Thank you so much! This was beyond my skill set. Your video clearly demonstrated how to create this shape.

[georgehobel]

not beyond your skillset anymore!