I love this website...and you get an additional %20 off if you buy the entire gallery wall. Cool, eh?

https://www.artfullywalls.com/walls?src=nav

Do you want something for one side, or both sides? Do you have any photos or artwork that you want to incorporate into the arrangement, or are you starting from scratch? I think it is hard to do from scratch (though you can go the route that Hiccup suggested). I generally prefer art that is personal to the person who chose it rather than generic pieces chosen to fill a space. If you aren't interested in taking your time looking for art you love, you could use your own photographs.

I've seen successful gallery walls where the pieces were all of a theme (say black-and-white architectural photos), same size, same mat, same frame, and arranged in a grid. But I've also seen successful walls that were much more eclectic. With an eclectic wall, you have to focus on visual balance of color and white space. It is enormously helpful to either do a virtual mock-up (take pictures of everything and do a digital collage so you can move everything around until you are happy), or at least lay out your actual pieces on the floor until you have an arrangement you're happy with (before you start putting holes in your wall)

I think that's very do-able. Uniform sizes, uniform frames, uniform mats. The trickiest part then becomes getting them all hung evenly. I'm afraid I don't have any good tips for that--maybe someone else can chime in about the mechanics.

The space to the left of the window looks like you could fit either 9 frames (3x3) or 6 (2 high by 3 wide) using frame sizes similar to your inspiration pic. One thing to be mindful of is the spacing between the frames. Too wide and your gallery wall starts to look not so cohesive.

Hang curtains on your windows like your neighbors did and do your gallery wall elsewhere.