Most of the OpenLI documentation is in the Github Wiki. Start with installation for Debian apt based or Redhat rpm based systems.

Move on to configuration. Examples are in the /doc folder of the source code.

Also in the Wiki is a complete video tutorial series on installing, configuring and performing intercepts with OpenLI. This comes with docker images to make installation easy.

A hosted version of the tutorial is available at APNIC Academy (free account required)