Idiomatic Guide to migrating from `json.NewDecoder(<bytes>).Decode(<interface>)`

[Wes McNamee]

I'm trying to figure out what the idiomatic way of migrating from using json.NewDecoder(<bytes>).Decode(<interface>).

I'm not sure what the correct way of using this library like I would by adding UnmarshalJSON to each struct that I have specific instructions for.

Is there a fully fledged example of doing deep json unmarshalling?