^^
Hi, there aren't any specific tutorials for making repacks. Inno is used for making installers, not the repack itself. Making repacks is based on doing research and gaining experience.
Here's a few tools I would recommend for starting out:
DiskSpan GUI - for compressing, aka making the repacks:
https://fileforums.com/showthread.php?t=104507
ASIS - for making the installer, so you can unpack the archive DiskSpan creates:
https://fileforums.com/showthread.php?t=99481
Additionally, you can browse the 'Best Compression Methods for 'Specific' Games INDEX' thread, to find out what method works for certain games (
https://fileforums.com/showthread.php?t=101639)