What is the proper way to wire a KF465?

Both inputs are wired in parallel so the simplest wiring configuration is probably to use one 2 conductor cable wired to pins 1 and 2 from your LF
amp to one connector, and another 2 conductor cable wired to pins 3 and 4 from the MF/HF amp to the other connector.

Running both the LF and Mid/High passbands off a single 4 conductor cable is also acceptable and standard practice in most bi-amp applications
(but you want to make sure you don’t have active connections on pins 1 and 2 across both connectors, that would have both amplifiers powering
your LF driver).