I have a graph file like this:
digraph { \"Step1\" -> \"Step2\" -> \"Step3\"; subgraph step2detail { \"Step2\" -> \"note1\"; \"
Use the command: rankdir=LR;
digraph { rankdir=LR; "Step1" -> "Step2" -> "Step3"; subgraph step2detail { "Step2" -> "note1"; "Step2" -> "note2"; "Step2" -> "note3"; "Step2" -> "note4"; rankdir=TB } }