Screen display RH brake light faulty

And when I use the brakes it makes a scratching noise almost sounds likes steel on steel. Sorry if I seem stupid but im a lady and I dont know whats going on with my citroen c2 vtr 1.4

I bought the car second hand and im worrying about what the expenses will be for taking the car to the manufacturer.

The citroen screen display says rh brake light faulty and it makes a steel scratching against steel noise when I use the brakes, can u pleasssse help me with this problem

thank you in advance
anele