feat: Updated docs/tutorials/multistep.md

docs/tutorials/multistep.md

@@ -16,20 +16,24 @@ steps:
       config:
         pdb_code: 1aki
       output_pdb_path: '&protein.pdb'
+      input_pdb_path: '*protein.pdb'
 - fix_amides:
     in:
       input_pdb_path: '*protein.pdb'
       output_pdb_path: '&protein_fix_amides.pdb'
+      input_pdb_path: '*protein.pdb'
 - fix_side_chain:
     in:
       input_pdb_path: '*protein_fix_amides.pdb'
       output_pdb_path: '&protein_fix_side_chain.pdb'
+      input_pdb_path: '*protein_fix_amides.pdb'
 - extract_model:
     in:
       config:
         models: [1]
       input_structure_path: '*protein_fix_side_chain.pdb'
       output_structure_path: '&protein_model_1.pdb'
+      input_structure_path: '*protein_fix_side_chain.pdb'
 ```
 
 </td>
@@ -44,6 +48,15 @@ docs/tutorials/multistep1.yml.gv.png
 
 ## Explicit Edges
 
+When defining explicit edges between output and input files, the following rules should be followed:
+1. Use the `&` prefix for the output file and the `*` prefix for the input file in each step.
+2. The `&` prefix must come first and can only be defined once for any file.
+3. After defining the `&` prefix, you can use the `*` prefix multiple times in any subsequent steps.
+
+For example, when connecting the output of step A to the input of step B, use the following format:
+- Step A output: &fileA.ext
+- Step B input: *fileA.ext
+
 The first thing you might notice is that all of the filenames are prefixed with `&` and then `*` (and they are in quotes). This is the syntax for explicitly creating an edge between an output and a later input. Note that `&` must come first and can only be defined once, but then you can use `*` multiple times in any later step.
 
 Note that if you just use regular filenames, they are treated as inputs which are external to the workflow, and thus are assumed to already exist on your filesystem. For example, if we remove the `&` and `*` around `protein_fix_amides.pdb`, we will get the following error message: