The data needed and the formula for the field calculator can be downloaded here:

https://ugm365my.sharepoint.com/:f:/...

I use land use and DTM because we wanted a simple flood risk map, you can change it depending on the complexity. The scoring is also very simple, you can use your own score. What I show is only an example. You can use it on both QGIS and any other GIS software with some change.