In our help documentation, we provide both a very basic algorithm to use as a sample and a multi-SID example. This is the multi-SID example.
You should press the "Clone Algorithm" button below, and that will clone the code into your "My Algorithms" page. You can then hack it to your heart's content! Try using different stocks, different buy/sell logic, etc.
The comments on this algorithm are fairly detailed, and should be helpful in setting up your own multi-SID algorithm.