Try using Ctrl+F to find what you're looking for. Eg. Your carrier you're building is called USS Imperialist Agression, just type that in into Ctrl+F and find when it is to be made, then change the date. Open the file in Notepad by the way. To add researched techs Ctrl F 'techapps = {' and add the number ID of the tech you want to have researched. You can find these techs (for eg. naval) in "C:\Program Files (x86)\Steam\SteamApps\common\darkest hour a hoi game\Mods\Darkest Hour Full\db\tech\naval_tech"
Just experiment and look around the file to get the hang of it