Getting an account on Piz Daint
You need first to be part of one of the UZH projects. Check with your supervising professor. The projects are called uzh1, uzh2, etc. Once you know you project identifier, then go to this CSCS web page. If you don't have already a CSCS account, then request there a new account and indicate in the form your project identifier. If you already have a CSCS account, then ask your supervisor to add you to his or her project, by sending an email to user-admin[at]cscs.ch or help[at]cscs.ch.
Getting an account on the large memory nodes Hydra
If your supervisor already has access to Hydra, then you need to send an email to Roland Bernet sysadm[at]physik.uzh.ch with a copy to help[at]s3it.uzh.ch requesting an HPC account. Note that a UZH login (or UZH short name) is required. All university employee have one. For external, you need to request a temporary UZH login to Roland Bernet, specifying that you need also the HPC account. If your supervisor does not have access to Hydra, then contact directly S3IT to set up a meeting.
Getting an account on the GPU nodes Vesta
You need to follow exactly the same procedure as for Hydra, except you have to specify that you need access to the GPU cluster.
Getting an account on the Science Cloud
If your supervisor has already access to the Science Cloud, he can add you as a member of the group him or herself. Note that again you need a UZH login (UZH short name). No need to activate the HPC account in this case though. If you don't have a UZH login, ask Roland Bernet to open a temporary account as an external. Note that if you don't need to manage instances yourself, your supervisor can directly create an account for you on the group's virtual machines, without any additional hurdle.