Default login is user password 1
Note: if you set your own password during the first run, you should use it instead.
Use ssh firstname.lastname@example.org from Linux or Mac. Windows users can use Putty ssh client. Once you are in run sudo -s to become root user. Start or stop miners, agent, etc. only from root user.
If you prefer graphic UI, VNC server is there for you. Use VNC Viewer or any other VNC client to connect to your IP address vnc://192.168.0.xxx:5900.
There is a Shellinabox server running on the rig. You may open https://192.168.0.xxx:4200/ in browser and access shell from the web.
And of course you can connect monitor to the first GPU in 16x slot if there are some serious problems.