Controlling and customising your installation is done via two methods which depend on the kind of changes you want to make.
Configuration refers to environment variables passed to the application at startup time. The kinds of things under configuration don't change very often once set, so they require a restart to take effect.
Settings refer to changes you can make via the administration menu inside the app itself. These are the kinds of things you'll likely want to experiment with or change more often so these are stored in the database and can be changed at any time.