There are several methods, depending on what you want to listen to.
If you just want to quickly listen to the audio file, rename the .m4b to '.m4a' on your computer before uploading it to your Android. Since the encoding is very similar, any regular Android audio or music app should be able to read it like any other normal mp3 file.
If you want to handle it like any other audiobook file, meaning you want to stop and listen to it later via an automated bookmark, there are several good audiobook .m4b file readers out there.
The best way is to do a search in the Google Play using the term '.m4b'. Several good ones should pop up.
One that can be recommended off the bat is Smart Audio Book Player. It is free to use on a trial-base, and then reverts to the basic options after 30 days, but those are plenty to listen to your books. And even so, the app goes for about $2, so that is worth it.