Well, again, read and apply the instructions contained in the read-me. And
please focus on the initial archive file you downloaded, with a size of 77.95MB, that is simple and fine at this stage, as I mentioned above.
ALL INSTRUCTIONS ARE AT THE BEGINNING OF THE READ-ME. Please read and apply carefully.
Don't worry about the DGen.exe, just drop it in your game main folder, again as explained in the read-me and indicated above.
Please at this stage don't bother about the modded version and other optional sub-archives, you should first make sure that the standard campaigns' files are installed properly, exactly as per instructions in the read-me (first pages). It will work!
Since your game is modded already, after that I just recommend you
install the flyable Curtiss H-75A-3 and A-4 from SAS from the link I also gave you (cockpit for Curtiss H-75). That will allow you to fly the Hawk 75, you should first test it in the QMB to confim.
Actually when you have a modded game, the option to use the P-36A-3 appears even in the standard version of my campaigns, and therefore it is better to have it made flyable in your game before. This is not a map issue.