Welcome to part 2 of the "Building a polygon boat" tutorial. Just like the first time, this tutorial is going to also have a video showing each step that needs to be made.
Chapter 2 - Building a polygon boat
Part 2 - Some adjustments and finishing the cabin
It is highly recommended that you watch the videos in order. Before continuing make sure you've watched part 1.
This is the link to the video tutorial of part2 - http://www.youtube.com/watch?v=uISj2cid6dw
Make some more adjustments to the shape of the boat. Try to keep it nice and simple and use the video as a reference.
Now that that's done, let's start building the window for the cabin. Use two edge loop cuts and cut the surface in two places, where the top and bottom of the window will be. Then add another edge loop cut, this time vertical and create the side limit of the window. The newly polygon in the middle of this whole thing should be proportional to the dimensions of the cabin's wall.
Select this large polygon and extrude it inwards, but not too much. There you have - it's the window.
Another smaller window should be added on the side of the cabin, So head to that wall and start doing some edge loop cuts, just like before. Two horizontal cuts should be enough this time, one for the bottom and one for the top of the window. The sides should already be there, if you've followed this tutorial step-by-step.
Watch the video closely and observe how the vertices are translated. The shape does not necessarily need to be exactly rounded, just try to make it look like that. After the vertices are in place, select the four faces where the window should be and extrude them inwards just like you did with the bigger window earlier.