Questions regarding burning Blu-Ray movies.?

I recently bought a external blu-ray burner for my MacBook, but I am not the most tech savvy person and a newbie to the movie burning thing so I need some help. I am using Toast 11 Titanium to burn. I have looked on various torrent sites for blu-ray torrents. I have downloaded a few movie files with .MKV extensions. Each file is about 6GB-9GB in size. Are these the right files? Assuming the MKV files are the files I need what comes next? Do I just drag and drop the MKV file into Toast 11 and press burn? Do I need to convert the MKV file to another format to get the full Blu-Ray quality? Are there other steps necessary before? Basically, the question is how do I burn MKV files to a Blu-Ray disc to play in a Blu-Ray player with Blu-Ray picture quality?