Hello reaper, welcome to the forum.
Create folder /mnt/us/extensions - this will be the home for all your extensions. If you connect your kindle via USB then create folder "extensions" (all lower-case letters, no quotes) in the root of your USB-mounted kindle.
If you can run KUAL then KUAL warns you when it can't find the extension folder. KUAL displays
KUAL • 1
• No extensions found
Save and reset KUAL log
where the indented items show up when you select and press the "KUAL • 1" button in KUAL. If you then click the "• No extensions found" button KUAL displays "help @ http://bit.ly/UW3v8V" - the bit.ly link points to this very thread.
OK. After you have managed to create the extensions folder find some extensions you like and that are compatible with your kindle model.
Follow the links in the first post to find some extensions.
Got the extensions?
Each extension is an archive file. Unpack it in a folder under /mnt/us/extensions a.k.a. folder "extensions" (all lower-case letters, no quotes) in the root of your USB-mounted kindle.
Start KUAL (again).