Make sure you can log in to Puhti and Mahti (if you are interested only in one type of CPUs you can use just that system). Create your private scratch directory along the general instructions and clone the course github repository there.
Try to run lspcu both on the login node (just lscpu in command
line), and in a compute node, i.e. via batch job script (srun lscpu). Are the CPUs the same?
Investigate the NUMA configuration in Mahti:
numactl -H
Try both login and compute node.