I would like to run some iCESM simulations and I have a small allocation of time on Cheyenne to do some initial tests. I ran some CESM1.2 simulations years ago on Yellowstone, but I'm a little unclear about how to get started with iCESM on Cheyenne. I see that the CESM1.2 code is located at "/glade/p/cesm/releases/cesm1_2_2/". I also see that some documentation is provided at NCAR/iCESM1.2. Is there other material that describes how to get started? For example, my very first issue is that, when I try to use the "create_newcase" command, "cheyenne" isn't a valid choice for the "mach" option, so I feel like I'm missing something. Any tutorials or advice that you all could offer would be most appreciated. Thanks!