The roof of my house is covered with flat rectangular red tiles, made of some kind of clay.

Some of them have broken and need replacement (for the ones within reach and as a temporary measure I have used sealant to cover the empty gap where the water can get in)

1. Where can I find this type of tiles?

2. How are they fixed to the roof?

I cannot figure out how they are fixed to the roof. I know there are some horizontal studs but the tiles (with the usual overlap between them) do not seem to be fixed to the studs, at least in the ones that I have inspected. Can they just rest in place by gravity? I doubt it because the slope of the roof is very steep, about 60 degrees. Could there be some with holes where they are fixed to the wooden studs?

3. How does one go about replacing tiles in such a steep roof?

Thanks,

Antonio