Two Problems

I have recently downloaded a torrent of the movie Riki-Oh and have two problems. The first problem is that the file type is not known to my computer. The file type is R01 - R45 (there are 45 files like this, that is why it goes to R45). The second problem is just that, there are 45 segments of this and it is a feature length movie. I need help with this please.

Get WINRAR, select all files, and extract to a directory.

If there is R01-R45 there should be a RAR put all of them in the same dir and open the rar