Under your settings on the Kindle you will find a Dictionary menu to change your primary dictionary. The newer E-ink Kindle Readers and iOS Kindle App will allow you to change your dictionary at the time you lookup a term. Each Kindle model is slightly different but you should be able to find help for most models here. Newer Kindles will search through each of your dictionaries until it finds a definition, but I would still recommend making the Fictionary your primary so that common terms or names that are also historical are matched to your Fictionary first instead of your standard dictionary. For this same reason it is recommended you do not install multiple Fictionaries from one series on your Kindle at the same time to avoid spoilers.
Use your Kindle email address provided by Amazon and email the Fictionary mobi file to your Kindle directly. You should also be able select this option after checkout and follow the on-screen instructions. The detailed instructions can also be found here.
Download the "Send to Kindle" application from Amazon. Once the Fictionary is downloaded you can send it to your Kindle with a click of a button.
Plug your Kindle into the computer and copy the Fictionary mobi file from your computer into your dictionaries directory on your Kindle. Steps are shown here.
Download and install the Calibre E-book management software.
Drag and drop the Fictionary mobi file into the Calibre window.
Plug your Kindle into the computer
Right click the Fictionary mobi file and select "Send to Device" and then "Send to Main Memory". If those options are not available your Kindle probably was not recognized by your computer. This software can also be used to change the file to an epub which can be used for reference purposes in iBooks or a Nook, though not as a look-up capable dictionary
The easiest way to use Fictionaries on Androidtm is to use the ColorDict App. It provides dictionary support to many apps on the Android platform.
Popular e-readers that use ColorDict include
FBReader, Moon+ Reader, Cool Reader, ezPDF Reader.
Once the Fictionary is downloaded the zip file just needs copied into the sdcard/dictdata directory on your Android device.
To do this you can download or email the file to your device and copy it to the dictdata directory using a file manager app or you can plug the device into a computer and drag and drop it into the dictdata directory.
From there, the Fictionary should work using the apps listed above - you can use the ColorDict app to arrange dictionary priority if desired.