Pat yourself in the back for a job well done. This chapter might not be the most advanced of the book, but the content was probably the heaviest. You now have a working knowledge of the different string types, collections (arrays, slices, and Vectors). You know about trait and implementation blocks, and you know how to work with constant values.
Armed with these, we can proceed to the next chapter, where we will talk about how error situations are handled in Rust.