to add new branching ratio node, go to toolbox tab, add branching ratio subtab, then:
  1. specify where to insert the new branching ratio by clicking on the desired location on the left
  2. select equation type
  3. compose new equation by dragging and dropping decay modes into equation fields br1.png
  4. Click verify and render to see preview of new branching ratio, then click \'create branching ratio\' if the display is correct.