NukeX is installed along with Nuke (see Installing Nuke on Linux). If you already have Nuke installed and have obtained a license for both Nuke and NukeX, you automatically have access to the NukeX features, including FurnaceCore. During the Nuke installation, four shortcuts are created for you: one each for Nuke, NukeX, Nuke Assist, and the Nuke Personal Learning Edition (PLE).