A bit weird. The pictures on the last two pages of the document tomstorey found count 26 contact fingers, that would suggest a 52 pin bus, but the table does show indeed 56 signals.
You still got a bit of a learning curve ahead of you. Designing symbols and footprints is pretty quick. The most complicated part is finding the actual information you want in your symbol or footprint.
Below a screenshot of the schematic for a backplane project I designed. It has one custom symbol (J1 on the left), and for the others I used standard library footprints. This symbol is also going to be used for the daughter cards, and therefore helps with keeping the signal names correct. (Also, check out how the “pin Helpers” work (New in KiCad V8)).
I have also sorted the wire labels in 4 columns, according to their function. This was quite handy, because signal order changed a few times during this project.
The thicker wires are created automagically by setting the netclass for power nets.
For the footprints, you will need two of them. (Male and Female). The male is probably some standard connector (or use the footprint wizard for S-DIP, and modify the result a bit) , for the female, you can use two arrays of SMT pads.