My RSTS PiDP11 error

My RSTS/E 7 with tape drives, works on my simh, but it doesn’t on the PiDP-11 simh, neither do many of the commands. I have no idea how to start it. It’s pdp11 on my system. The instructions say “In short, read the two simh manuals: the general simh manual and the simh-PDP11 manual. I googled and had a hard time finding the simh-PDP11 manual

Default memory allocation table specifies some existing memory
as being nonexistent.

Table will be reset by RSTS.

  Memory allocation table:

     0K: 00000000 - 00207777 (  34K) : EXEC
    34K: 00210000 - 00303777 (  15K) : RTS (BASIC)
    49K: 00304000 - 16777777 (1871K) : USER


  Table suboption? EXIT

You currently have crash dump enabled.

DD-MMM-YY? 85.1.1
12:00 PM? 0:0
BUFF.SYS not found or too small - DECtape disabled

16 devices disabled

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