To do this correctly, if it is an idc connector, requires a special tool. Cable manufacturers use bench presses with dies and jaws made for the type of ribbon cable and connector. Very expensive.
There are hand tools made for these but they are ridiculously expensive. A satisfactory result can be obtained on a bench using something as simple as a 'T'-type tool, but it is a pain to do and the risk of scoring the conductors is high. Still, it can be done. The other part on top of the connector is simply a strain relief. Use is optional, but really handy if your gear is being moved about.
It is a neat looking solution, using ribbon cable and idc, but crimp is always better and easier for diy. Also, some of tis style of connector are available in an idc OR a crimp version.