It's a bit like asking: how do I build a house?, but I'll give it a shot.
In general, after offline editing, a conform needs to be done at final resolution. Traditional conforming would mean the cutting of the actual original camera negative film. That conformed negative film could then be printed for theatrical distribution copies (although usually, intermediate safety copies would be made first). Most effects would have to be made by ordering opticals from optical houses (analog photographic processes), or would have to be done digitally (transfer to digital files first, processed digitally, then burnt to film again). Grading of the image would be done by a color timer, which would determine the exposure levels during printing.
In the last decade, the digital intermediate process has taken over most conforming. That means that all shots that were used in the edit are retransferred from the original camera negative to a digital file (or sometimes tape), then conformed to the offline. All effects are conformed/added/enhanced there as well. Grading also happens in the diital domain (allowing much more manipulation than is possible in trditional color timing). Afterwards, the digital intermediate will be recorded onto film by machines like an ArriLaser (you put digital files in and it will burn them to 35mm interneg or interpos material). Afterwards, 35mm prints are derived from that and distributed.
About DI:
http://en.wikipedia.org/wiki/Digital_intermediate
About ArriLaser:
http://en.wikipedia.org/wiki/Arrilaser
Since stuff like the ArriLaser allows for high quality film recoring of digital sources, any digital source is possible. So you can shoot a film on video (SD or HD) or with a digital cinema camera (Red, Sony, Thomson et al.), process everything digitally, then record to film. You could also transfer 16 or 35mm film to (HD) video, edit that, and record it to film. Digital grading can be done on various types of equipment, with different pros and cons (linear versus logarithmic color space).
In modern cinema post production, many ways lead to Rome, and workflows vary from simple to complex, from expensive to cheap, from high end to low end.
