DesignBuilder models can be customised to allow you to enter the level of detail which is appropriate to your building design or modelling project. In early-stage design work you will generally want to use generic selections for most Model Data and so would choose the corresponding 'low data requirement' model options.
As the building design firms up, more information becomes available and you can change the model options to use more specific data tailored to the project and less generic data.
The 'standard' Model Option set is loaded at the point the building is created and you should generally keep these options unless you have specific reason to change.
Model Options are set in the Model Options dialog from the Edit menu.