This is for those who are coming from a clean install of the IL-2 Sturmovik 1946 DVD. That has version 4.07m. You will first need to update with the 4.08m patch, and then the 4.09m patch, before moving on to the mods.
Once you are on 4.09m, you can fully install the Ultrapack mods up to version 2.0 by going here.
Download the 7 parts to a new folder, so that those 7 parts and only those 7 parts are in it. During downloading, note the projected file size, and confirm that each file actually is that size when done. After downloading is complete, but before installing, check for file corruptions, using the test feature in WinRAR on the part 1 exe. If any parts are found to contain corruptions, trash and re-download those parts. Do this until it doesn't give you any corruption messages at the end.
Now for installation, double click on the exe and let it extract. It will go through all the files, and then ask you to define the location for installation. If it's not on the main IL-2 Sturmovik 1946 directory with 4.09m, make it so, and install.