Hi there! It definitely depends on what you're looking for. At the very core, LinuxONE is your traditional Linux distributions (officially supported are RHEL, SLES, and Ubuntu), so if you're familiar with those, you're already familiar with LinuxONE. Beyond that, if you're looking for how they actually function with the hardware, how to do installation and configuration, etc., there are the IBM Redbooks that dig into various specifics (text, not courses): http://www.redbooks.ibm.com/redbooks.nsf/domains/linuxone
There's also specific documentation out there for specific pieces of software, like if you're interest in using OpenShift (https://docs.openshift.com/container-platform/4.4/installing/installing_ibm_z/installing-ibm-z.html) or specific software packages, see: https://www.ibm.com/community/z/open-source-software/ & https://github.com/linux-on-ibm-z/docs/wiki
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Elizabeth K. Joseph
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