FSX uses a specific layout for it's file directory in order to work correctly. To implement DLC, we've had to make sure that we don't affect the base file structure too much. As a result of this, each piece of DLC is stored in a folder within the 'DLC' directory in FSX.

You can find the DLC folders here, by default:

C:\Program Files (x86)\Steam\steamapps\common\FSX\DLC

 To find the DLC manual(s) in this folder directory, you can do the following:

1) Go to the Steam page for the DLC, for example The Friday Harbour (KHFR) Add-on ( http://store.steampowered.com/app/379235/ )

2) Note that the number in the URl is the DLC AppID from Steam, in this case 379235

3) Go to the 379235 folder in the DLC folder

Note: Some manuals may be in a 'manuals', 'text files' or a similar named folder.