A Group in your Brutus Options Ranker strategy gives you a way to organize similar criteria into a branch in your strategy tree. This keeps your strategy tree organized and allows you to assess the rank of the group by using sub-criteria.
For example, you might want to use multiple criteria to assess the potential profitability that the Brutus Options Ranker evaluates. In this case, you could drag the "New Group" block from the criteria panel into your strategy and give it the custom name "Max Reward".
Once the group is created, it's score will comprise of the evaluations from each criterion you list below that group. For example, you might want to maximize return on capital as well as IV Percentile. You will drag each of the sub-criteria into the new group as in the screenshot below: