Hi Ian,
As far as I know the K-2 is not compatible with the 1v/octave Eurorack default (the K-2 is a clone of the Korg MS-20), so you might need a converter. Luckily for us that Behringer plans just a module like that for Eurorack, the "961 - Interface" module, not available yet though. So this 961 together with K-2 should do the trick.
Kind regards, Garfield.
For review reports of Eurorack modules, please refer to https://garfieldmodular.net/ for PDF formatted downloads