Hey, thanks for the screenshot!
As I mentioned in the email, FL Studio will create different groups based off the type of content you are adding into the Channel Rack.
If you load in one-shot drum samples, this is under “Unsorted”. If you load in audio files, FL Studio will create an “Audio” group.
This can be accessed on the drop-down menu of the Channel Rack, or you can switch to “All” to view everything added into the Channel Rack, but I do not advise that.. just use “Unsorted” or “Audio” to navigate your sounds.
To add a sound into the Channel Rack, you simply drag an audio sample underneath a previous sound, you’ll see a green bar, then just let go of the mouse button!
For your Channel Rack locked into place, I’m not sure.. I would have to see a video..
Are you not able to resize it from the left or right at all?