Good point, Parker.
So, one has to pair the two devices, then to connect the Dot to speaker, one needs to tell the Dot to "Connect bluetooth" and tell Dot to play music, tunein station, etc. If all went well, to stop playing, tell Dot "disconnect bluetooth" and it will do so and say something like "next time when both are turned on again they will automatically connect and start playing.
As an example, this is what I just did: I powered up my portable BT speaker. I heard a couple of sounds that indicated it "connected" to the previously paired Dot. I told Dot to play tunein statiom XXXX, and it did so through the BT speaker.
Then, to complete the circle, I told Dot to "disconnect bluetooth". It did, and said it had disconnected from the specific BT speaker. The music came out of the Dot speaker, I told Dot "stop" and it did, I turned off the BT speaker power then, and am ready for the next time to connect them again.