This is pseudo-content plugin that intended to perform some tasks at Total Commander launch. You can run a file, execute TC's command (both cm_ and em_), set environment variable, set delay between commands, write value to ini file, load library or plugin. Commands are reads from text configuration file.
Autorun distributive also include additional plugins that expanding it's possiblities:
Forum wincmd.ru (Russian)
Before installing plugin recommend to rename autorun.example.cfg file into autorun.cfg, and edit it if needed. Installation of plugin is usual for content plugins. Next, in order to load plugin at Total Commander start, you should create the fictitious color scheme:
If you have many color schemes, it's recommended to move Autorun scheme to the top of list, else it can not run sometimes.
Plugin can be renamed, in this case change the name of configuration file correspondingly.