Also, since you mention the sandbox directory, I'd recommend thinking of "exploring/experimenting with the sandbox" as a separate activity from "starting a project". In other words, rather using the sandbox as the basis for your project, I'd start out by
following the sandbox instructions to become familiar with Oscar, but once ready to start a project, I'd start a new, clean Django project, with Oscar installed and configured as a module,
following the getting started instructions. I'd keep the sandbox around as a reference for when things get complicated.