Here you have 2 options.
1. Install fom iso, but remember, I didn't manage to install under IRIX (problems with JVM). I Could install it under windows and then transfer whole moe directory to irix (just be sure to make moe file in bin-sgi4 folder executable) and copy license.dat from Lz0 to moe directory
2. Just unarchive the second file which is complete installation to your IRIX disk and run.