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A good first place to look for all low-resource languages is the Bible, portions of which have been translated into an incredible 2932 (!!) languages. In many cases, there is even a dramatized audio recording available, which is super helpful if you aren't able to immerse yourself in a fluent community while learning.
The entire Bible is translated into Twi. A quick search even pulled up an app that displays it side-by-side with (old) English:
https://play.google.com/store/apps/details?id=com.TwiBibleApp.android&hl=en
Audio download:
http://twibible.blogspot.sn/2008/04/twi-audio-bible-in-mp3-free-download.html
If this is your first time using the Bible for language learning, I would start with a narrative book, such as any of the first four books of the new testament (Matthew, Mark, Luke, John) which include lots of short stories, often with dialogue.
Another resource I have found to often be useful for minor languages is the Peace Corps, which has created (but not always widely published) language learning resources for their volunteers. Like I said, they're often not officially published, so you might have to do some scrounging.
http://files.peacecorps.gov/multimedia/audio/languagelessons/ghana/GH_Twi_Language_Lessons.pdf (manual, missing audio) https://www.livelingua.com/project/peace-corps/Twi/ <- might have audio parts?