5100-5900 series engines -- how to install the couplers

[hatpastor]

Hello,
I am fairly new to HO trains.  I bought a great engine of the 5100 5900 diesel engine.  I have no clue how to install the couplers that came with it.
I figured out how to remove the shell, and have the part 11 and 10 removed, but don't know how to put the two coupler parts on it.

[rich1998]

A suggestion. Point out exactly which loco, not just the series.

Rich