If it's not already installed, you can download
and make sure that it gets unpacked so it creates a new directory /opt/pidp11/systems/nankervis (so I guess you have to unpack in the /opt/pidp11 folder).
Then select 1000 (octal) on the switches to the left of the white "lamp test" switch, and reboot the machine. This will start the 11/70 simulation with a special bootloader that lets you decide (by typing into the console) from which of many (simulated) drives you boot, and each of them has a different OS on them. You get into the console by executing
~/pdp.sh
on the Raspberry PI (e.g. via ssh or directly if you have a keyboard and HDMI monitor connected to the Pi).
Inside the tarball that you unpacked above, there is a PDF describing the boot procedure for the different systems in the collection. I think that's all you need to do.