The Flemish Supercomputer Center (Vlaams Supercomputer Centrum – VSC) is a consortium that provides high performance computing power and the maintenance thereof. For academic use, anyone at one of the Flemish universities can obtain an account that yields free access to Tier-2 systems. More information can be found on https://www.vscentrum.be/.
To gain access to the HPC, you will need to apply for a VSC account if you have not done so before. Please follow the steps at https://docs.vscentrum.be/en/latest/access/getting_access.html. In addition, the steps also describe how to set up your public/private key pair. These are tokens that allow you to log in to the HPC without a password. Note that the tokens are machine-specific and that you will need to set up multiple key pairs if you want to log in from multiple machines. Also note that it can take some time (~15 minutes) to activate your public key after uploading.
Finally, logging into the HPC makes use of the SSH (Secure Shell) protocol. Depending on your operating system, you may need to install a specific client to do so. For Windows, PuTTY is an often used client. For MacOS and Linux, you can use the ssh command in the terminal.
Further instructions can be found on https://docs.vscentrum.be/en/latest/access/access_and_data_transfer.html. Likewise, this page also describes the information to transfer data from your computer to the HPC and vice-versa. In Windows, the WinSCP is often used, while on MacOS and Linux systems you can make use of the scp command on the command line.