Vaxstation 3100 basics

I have managed to find and cobble together enough bits of hardware to have an operational vaxstation .... I think. I've never played with one before or even seen one. What now? The box is a model VS42A and has a 3.5" floppy and 2 X 100Mb internal SCSI hard drives. It has what looks like 8Mb of RAM to me, whatever is on the main board plus a 4Mb extension. On powering up it says KA 42-A v1.3, does a hex countdown and finishes with a ">>>" prompt. Command "b" causes it to display ESA0 and stop. Command "?" gives an error message. Command "c" causes a drive to start. It then displays an error message "ISP ERR PC=00000000" and then lists a table I can't decipher that seems to list drives and includes "VMS/VMB" and "Ultrix" along the top. It then has a prompt " [ESA0:] >>> ". At that point command "b" results in a series of errors: 83 BOOT SYS ?41 DEVASSIGN,B 84 FAIL How can I find out if it has an operating system? or have I already proved it hasn't? None of the stuff I have found on the web so far goes this basic. It looks like it is at least NEARLY 10 years old. Thanks Hans Olminkhof