Just to help you out here, @markopolo5437 - because it's non intuitive to start with, and we have all been there... do this:
As Ripley said - go to
http://users.kymp.net/p501474a/Orbiter/Orbiter.html and get the LunarTransferMFD or the InterplanetaryMFD for your version of Orbiter. (E.g. if you have just started, and picked Orbiter 2016, then make sure you get the Orbiter 2016 version). Why do we still have the older Orbiter 2010? It's because there's not 100% backwards compatibility, so there's many things that run on Orbiter 2010 but not on Orbiter 2016.
Also note that downloads from specific addresses like this is a bit non-standard: the vast majority of addons will be found on orbithangar.com.
When you download the addon, store them in a folder somewhere near your Orbiter installation. E.g. I have an O: drive for all my Orbiter stuff, with O:\Orbiter2010, O:\Orbiter2010Repo, O:\Orbiter2016, and O:\Orbiter2016Repo. The 'repo' folders are my file repositories for all the addons I download, plus the original installer ZIP files. Why? Because it's always handy to have everything local for when you want to set up a new installation, e.g. if you mess things up, or if you are doing a specific scenario where you want to install an exact set of addons in the right order.
Once you have your addon downloaded and stored in your repo, then take a close look at the file extension, as it determines what to do with it. You will have one of these:
- ZIP files. Noce & easy: Right mouse, Extract All..., Browse to your orbiter root (e.g. O:\Orbiter2016 for me) and hit Extract.
- EXE files. The addon writer has created an installer, so run the .exe and follow the instructions.
- RAR, 7z, etc. files. Pretty rare, and these are just a different zip format. Go to www.7-zip.org and download and install 7-zip, which is pretty much the king of all compressed file formats. Once you have this installed, you can open the compressed file and then target your orbiter install again.
Note that when unzipping or expanding these compressed files, they will have multiple files and a specific file structure inside. This is why it is critical to unzip all files, and just overlay it onto your Orbiter root, so the files will drop into the right subfolders.
Looking at IMFD for Orbiter 2016, as an example, the file is IMFD57.zip (at the time of me writing this). Double-clicking into the zip shows it has 5 sub-folders: Config, Doc, Modules, Orbitersdk, and Scenarios. This is a classical hint that this is an Orbiter ZIP file, as these subfolders map directly to the subfolders under your Orbiter2016 install. Have a look around for a couple of filenames: e.g. in Config, make a note it has IMFD5.cfg, and in Modules\Plugin, note InterMFD57.dll.
So, hit the back arrow icon to go back out of the ZIP back to the repo folder, and your IMFD57.zip. Right mouse, Extract All..., select your Orbiter2016 root, and press Extract. If it asks you if you want to overwrite any files, then you have either added it before, or the ZIP file shares filenames with other installs (e.g. the XR-series spacecraft share some common files). Generally I would advise to always allow the unzip to overwrite files, as the developer obviously intended for this package to install as one unit. But - that's also why you keep the files in a repo, so if you screw it all up, you can generally reinstall orbiter and all addons in under 15 mins.
Final checks ... in your Orbiter2016 root (e.g. my O:\Orbiter2016, or your C:\Orbiter, or whatever you chose), go find those couple of files you noted: in under Config ... you'll see lots of files, but IMFD5.cfg should now be there. Same under Modules\Plugin ... tons of files, but you should find InterMFD57.dll. (If you don't, then your extract didn't work, so retrace your steps and figure out what you did wrong).
Now you have your addon installed, you need to activate it. When you launch Orbiter.exe or Orbiter_NG.exe (the latter is used with the D3D9 addon, and gives you 10x faster graphics, by the way): in the Orbiter Launchpad (where you select your scenario), click on Modules, and then look for the module you have just installed. In this case: InterMFD57 will be there and unselected. Select it (tick in the box!), go back to scenarios, pick something simple (e.g. Delta-glider folder, Docked at ISS), double click it to launch. In the simulation, get to a virtual cockpit view (press F8 until you have 2 large green MFD displays), then press SEL 2x, 3x, times until you see Interplanetary, select it, and you should see the opening message for IMFD. E.g. for mine: *Reboot Completed*, Version 5.7, Date of build, Dec 16 2016.
Hopefully this detailed walkthrough is of use to you and to other beginners. Installing things can feel a bit complicated, but you will quickly get the hang of it!
Welcome to Orbiter, and to this Forum.