OSDev.org

I've been following (a very good) tutorial on the internet - which is teaching me quite alot about low level access and assembly; eventually to lead me on to full-blown OS dev.

BUT: Part of the tutorial is missing, and it skips from assembly stuff, right into coding with c#/c.

What I would like to know, it how are the c#/c and the assembly 'linked' as such? How do they come together?

not at all. assembler generates object files. same does c compiler. it's the linker that links the various object files together to an application, a library or - a kernel. btw i doubt that your osdev tutorial builds a kernel with c#. it's rather c++.