To install the mod, put the folders to
\Documents\My Games\Might & Magic Heroes VII\MMH7Game\CookedPC\
(unless you want to irreversibly overwrite the data; else you put the folders to your game location \MMH7Game\CookedPC\)

if any folder is missing in the path, create it.

The mod replaces the hero icons with their icons from previous Heroes Might and Magic installments.
From Heroes IV: Solmyr, Charna, Jenova, Minasli, Yog
From Heroes V: Eruina, Ebba, Dirael, Erling, Kaspar, Lethos, Lucretia, Maahir, Naadir, Nur, Ranleth, Ossir, Sinitar, Svea, Zoltan

Enjoy the mod!