I just found this
LibreOffice extension, which will export any file recognized by LibreOffice as an ePub file. Its use looks to be fairly straight forward. I tried it, but cannot view the file with Calibre, since Calibre appears to be broken atm (on my computer, anyways ... it creates windows on my screen that are all gray and devoid of the intended contents).
One other possibility might be to explore the use of Sigil, which is in the repos. There was an article in the magazine within the past couple of months about how to use it.
In either case, once the ePub file is produced, then Calibre can be used (hope it's working on your computer) to convert it to MOBI format.
Just a couple of ideas to throw out there.