Frustration with sample code

[jacobsapps]

I'm working through your book at the moment, and while I find it fascinating and extremely helpful, I'm left frustrated at the sections where we write 'our own code'.

I've installed the sample project and was working my way through the part in chapter 2 where it directs us to 'create classes ourselves' but found that the code I was being told to write was already fully written in the sample project - is there any place that we can write it ourselves? I'm just confused since the language you use is telling us to do all these actions, which seem to have already been done.