Coconut butter/manna can be found in the health food store or sometimes it's in the natural foods section of a regular grocery store. It is optional in case you can't find any. I add it for an extra bit of creaminess!
The texture is somewhere between a sorbet and gelato/ice cream. If you want it more creamy, I would suggest using 2 cans of ONLY the full fat cream from coconut milk and NOT the coconut water in the can. This would yield a more creamy texture. You can also remove the shredded coconut but I like the texture it provides.