Download Duokan for the KPW from here. (see the "Kindle Touch and Kindle Paperwhite" entry with the download link 安装包下载) Make sure you know that your kindle model is a KPW (see here for similar packages for older models)
Once installed the best (safest) method for running Duokan 2014 is by using KUAL This simply uses KUAL (Kindle Unified App Launcher) to activate Duokan. It is by far the simplest, safest, and most successful. However, it requires you to jailbreak.
Updating Duokan and using the wifi function in Duokan requires registration with Duokan's new owner xiaomi which can be accomplished in the application.