You just have to select the 'PAK / LSV Tools' tab and enter the Package path and the Extraction path (any location where you want to store the files; don't choose a game path here). Then press 'Extract Package'. Extracting the Icons.pak works fine for me. Raze linked version 1.7.2, there's a newer version (
Download), but it works with 1.7.2 as well.
If you're looking for information on how to change character portraits you should have a look on the mod page from 'The Internet' personally:
Custom Portraits for Enhanced Edition (Nexusmods).
