Combining D and C

[Matt]

OK, I'm reallly confused about this. If I have a C source file, and a D module, what are the things I'd need to create an executable from the two?

How would I go about reading functions and varables from D in C, and vice versa. I apologise if it is really simple, but I just can't find anything concrete on exactly what to do. I keep being told to use htod, but what am I supposed to do once I have used it?