firstly let me say great software. Used it a lot over the years but not recently.
So I the video file I have has the following audio channels
Channel 1: Left Front
Channel 2: Right Front
Channel 3: Center
Channel 4: LFE
Channel 5: Left Surround
Channel 6: Right Surround
Channel 7: Left Total
Channel 8: Right Total
1.1 .. 1.8 are just some numbers that DCP-o-matic assigns to the streams in your file. So in your case, 1.1 is your channel 1 (left front), 1.2 is your channel 2 (right front) and so on.
So 1.7 and 1.8 are left/right total which you could ignore, or add as a HI (hearing impaired) track.
The top row (output) in the matrix follows DCI/ISDCF/SMPTE conventions. The left row (input) of the matrix can not follow a strict convention other than plain 'channel number', because in computer video/audio files, there is no such convention.