I installed Kindle for android in my phone.
I have ebook in mobi format and mp3.
The mp3 is audiobook for the ebook.
I have put the mobil and mp3 in Kindle folder.
The ebook can read but how do I play the mp3 together and sync with text?
You can use Kindle narration to listen when reading. Open the Kindle eBook and tap on the screen, then hit headphone symbol you can listen to the book.
If you just want to listen to the audiobook, just use Audible for Android app.
If you would like to have the audio match the text then you would have to create a read aloud ebook using EPUB 3. You can learn more about this at this link