Separate code into smaller sections

[Albadylic]

When completing this workshop it was confusing how much code we should be writing in each step of the exercises. For example, in the first case we though we'd have to call the function in order to find the errors; in the second case we thought we'd have to write the try/catch block in stage 1 but all we needed to do to pass the tests was throw the errors.

Having an overview of what was to be completed in each step or adding to the explanation to say that only errors should be thrown may have made the exercises easier.

Relates #41