Ok the next stage is to get some actual code running.

I found a code sample here.

http://www.randomterrain.com/atari-2600-memories-tutorial-andrew-davie-08.html

created a local file asmtest.asm

Because I created a new terminal session I need to run these two commands again.

export bB=~/Atari2600/bB
export PATH=$PATH:$bB

I used this command to compile.

Joes-MBP:samples arkleyjoe$ dasm.Darwin.x86 asmtest.asm -I"$bB/includes" -f3 -lasmtest.list.txt -v5 -sasmtest.symbol.txt -oasmtest.bin

Open Stella, select asmtest.bin

Bingo.

Next up is to try some code I have actually written.

http://aboredprogrammer.com/2017/02/21/develop-atari-2600-game-part-1/