The Top-Down

1. Start Twin Builder, if it is not already running.

   If Twin Builder is already running, create a new project; select File > New.

2. Insert a design in the default new project or new project you created by selecting Insert Twin Builder Design on the Project menu.

   This will be the top-level circuit.

3. For each subcircuit you will need in the top-level circuit:
   1. Make sure the top-level circuit is active in the schematic editor.
   2. On the Twin Builder menu, point to Add SubCircuit, and click Add SubCircuit on the sub-menu.
4. Repeat step 3 at each level of the hierarchy as needed.
5. To reuse subcircuits at multiple places in a design:
   1. In the Project tree, right-click the icon for a design you want to reuse and select Copy.
   2. Right-click the icon for the design into which you want to copy the subcircuit, and select Paste.

   A symbol representing the subcircuit appears in the parent schematic. You can place and wire the subcircuit as desired.

As you create subcircuits, you will probably want to rename them. To do this:

1. In the Project tree, click the name of the icon for the design that you want to rename.
2. Click the icon name again.
3. The icon name changes to an editable string that you can modify. When you renamed the design name to your liking, press Enter.

Twin Builder creates a generic rectangular symbol for each new subcircuit. You can customize the symbol for a subcircuit as follows:

1. Expand the folder in the Project tree labeled Definitions, then expand the Symbols subfolder.
2. Double-click the symbol icon that corresponds to the subcircuit symbol you want to edit.
3. The symbol opens for editing in Twin Builder’s symbol editor.
4. When you’re finished editing the symbol, click Update Project on the Symbol menu to propagate your changes through the project.