Just use a ssh client :
ssh user@lcpq-curie.ups-tlse.fr
If you need visualisation on the cluster :
ssh -Y user@lcpq-curie.ups-tlse.fr
First you need to connect to UT3 vpn or LCPQ ssh gateway (lpqsv1) or vpn.
When your are connected through one of the previous method, just connect to curie with ssh.