You can start the graphical user interface (GUI) of COMSOL on one of the login nodes of Euler. This can be useful to change your COMSOL preferences or to prepare a model or check the result of a COMSOL job. In order to start the GUI of COMSOL on a login node, you first need to establish an SSH connection with X11 forwarding enabled.
ssh -Y username@hostname
With username being your ETH username. Afterwards, you can load one of the COMSOL modules
module load comsol/5.2
and finally start the GUI with the comsol command.
comsol -np 1
If the COMSOL GUI runs slow through X11, then please have a look at the troubleshooting section of this wiki page.