First of all, and strictly speaking you mean apps that need a rooted phone to work. Most of them can be found on the Play Store. Or alternatively all of them can be found under the Note 3 section in XDA forums.
You'll need to get the actual installation files (.Apk) on to your phone (just use the phone to download them) and make sure you have "unknown sources" checked in settings>security. One last thing make sure they are for your exact model of Note 3 and your good to go. Tap on the app in "downloads" in your device storage and install it.