The docker rm brewpi command worked. I had actually tried rm brewpi from my very limited CLI knowledge.
I retyped command and got erro "error gathering device information while adding custom device “/dev/ttyACM0” lstat /dev/ttyACM0: no such file or directory.
My Spark3 is plugged into the Raspberry Pi3 via mini USB. The Spark 3 is powered up and in hardware test mode. Two sensors plugged into spark seem to work fine.
I did find something earlier about needing to do touch calibration. However, when the Spark 3 starts up and asks for you to touch stylus on +, the + symbol blips briefly in top left and lower right corner. I do not seem to be able to calibrate. After about 30 sec, the Spark goes into hardware test mode.
Sorry if these questions are basic.