Hi Eduardo,
You can have a look at the file-storage package and the way it uses the CR API.
In most cases, if you just need to store files and nothing more fancy than that, then you can go right ahead and use file-storage (which I would recommend so you don't have to reinvent the wheel). In addition, since someone in the community mantains the FS package, you can relay on future improvements and maintenance. Summarizing: reusing functionality that is already there is a good idea 😉
However, if the functionality you are trying to implement requires a higher specialization, then you might want to user the CR API directly.
Ernie