I am working on making a castle from "Game Art for Teens: Second edition" by Lee Perdew.
Many parts of his book is confusing, and not very clear, plus the pictures are very SMALL if you want to look at numbers of xyz coordinates or whatever...regardless, I liked the models as it taught me a lot...until I reached this problem.

This is from Chapter 4 for those who have this book.

This is my screen shot from my model. In the circle is the problem I'm having. The book says, "Extrude the faces out from the wall .5 of a unit, as shown" - which is what I did.
"We need to do a little patch up work on the wall between it and the extruded section. Select the vertices along the outside edge of the extruded section and snap them over to the next set of vertices, as shown" (This is a photograph of the book, shown after this post).

I have tried a lot of ways, and I cannot get it to look the same...HELP please?