Mike seems to have covered most of what needs to be done. If I may add a few notes, however:
There seems to be a quirk with P3Dv3 and later. It requires AICarriers to be placed IN the main P3D folder to function properly. So, when you install, as you did, make sure it's under your P3D root folder. Like: C:\LM\P3D\AICarriers\, for example. Almost always, a failure of AICarriers to load when the sim starts is a fault in the EXE.xml file's path entry. It only takes what we would hardly consider an error. A capitol letter vs a lower case, a comma in the wrong place, anything.
Second, did you install the .NET version of AICarriers, from this forum, or the older, .exe version? I personally will only use the .NET version. It works perfectly on my Windows-7, FSX:SE.
Not only that, but did you install the .NET Framework 4.0 Client, as specified in the Readme file? Very important!
Do you have the latest FSUIPC from Doug Dowson? Another very important file.
Your memory serves you correctly, Mike, Shift+J will call the menu, presuming you have AIC in the EXE.xml correctly. Mike showed the proper way of adding an entry for AICarriers to the EXE.xml. If you do not have the EXE.xml file in the correct location, you need to create it. Remember to only ever use Notepad, which comes with Windows, or Notepad++, a freeware, easy to find and install. I utilize it extensively. Never ever, EVER use a word processor to edit any form of .cfg or .xml file, as they add symbols to the file, making it useless to the sim. Always make a backup before editing any file, as well. Critical step in the process.
Bear in mind, when you install a carrier's .cfg file to AICarriers, frequently, the length of the file will make the menu have multiple pages, rather than just the single you get when you first install AICarriers. The last entry on a menu's page will be a 0-Next Page entry. Sometimes, people don't notice them, or scroll far enough down to see it.
Finally, and then I'll shut up, when you start adding .cfg files to the ...\AICarriers\conf.d\ folder, don't just do so indiscriminately. In other words, there are a ton of boats, destroyers, cruisers, various carriers, and so on, and they all seem to come with an AICarriers.cfg file. If you keep adding more and more .cfg files to the conf.d folder, the menu in the sim will become unwieldly and very difficult to use to locate the ship or formation you desire. I've solved this by making a sub-folder under the conf.d folder, thus: ...\AICarriers\conf.d\BACK\ . I place all the .cfg files I've collected, and there are many, in the \BACK folder, and swap them in and out of the conf.d folder as I desire. I want the Forrestal, but not Javier's Nimitz? Just swap their .cfg folders before AICarriers starts. Or swap them, shut down AICarriers, and restart it with a desktop icon I created. This keeps the menu you get when you hit SHFT+J from winding up with 10 pages I need to search through to find the carriers and formations I desire.
It also keeps the conf.d folder from getting over-crowded, making it difficult to trouble-shoot troubles with a particular .cfg file.
Make certain that if/when you add a .cfg file, you start it's numbering with [Formation.0] not [formation.1], or AICarriers can not read the file.
Many add-on ai boats that come with an AICarrier's .cfg file, recommend to add their file to the main AICarriers .cfg file. I strongly recommend against doing this, as again, it makes the Menu unwieldly very quickly. Make them their own .cfg file with a unique name, and place it in the .conf.d folder, or your \BACK folder for later use. Leave the main AICarriers.cfg file alone.
Lots or words, but I hope some of them will help a bit. Thank you very much. Mike, for the assistance. Very good information, and well presented.
Enjoy! I sure do
Pat☺