you need to install the amazon reader app onto your phone, here is the link.
http://www.amazon.co.uk/gp/help/cust...deId=201245160
To download and install Kindle for Android from your phone:
Go to Kindle for Android .
https://www.amazon.co.uk/gp/feature....cId=1000423873
Follow the instructions to download the app to your device. After installing the Kindle reading app, you'll need to register it to your Amazon account.
once that is installed, your phone will fetch fresh copies of your mobi books directly from amazon. calibre is not needed for that process,.
get that working first, then come back for advice on how to get at any other books that you bought elsewhere.