How do I import multitrack recordings?

Er, that's not a strange mono recording - that's a multitrack file! And in that form, in Multitrack view you can do pretty much nothing useful with it.

There are two approaches to how you deal with this - you can either open the file in Waveform view and split the tracks out manually, or you could try doing what Adobe recommends, which is to follow the steps outlined here. If this doesn't work out, then I can detail what you have to do to extract them into separate files, but you should really try the 'official' method first - which can be summed up by saying 'hold the Alt key down whilst dragging the clips onto the track layout'.