For future reference, this is totally a Kindle question, not a calibre question.

We have a whole
Kindle forum here at MobileRead, and the Kindle experts hang out there while the calibre experts hang out here.
Which isn't to say there isn't some overlap between the two groups.
...
The best way to thank the forum members for providing help is generally to pass the help on. Many of us began where you are, getting help from the veterans until they themselves became veterans.