To copy a model to another file in SketchUp Pro 2023.1, open the source file containing the model you want to copy. Use the Select tool to highlight the entire model or specific parts you wish to copy. Then, right-click and choose “Copy” or use the keyboard shortcut Ctrl+C (Cmd+C on Mac). Open the target file where you want to place the copied model and use Ctrl+V (Cmd+V on Mac) to paste it. Position the model as needed in the new file. Make sure both files are compatible and that the target file is set up to receive the copied model correctly.