How to Add Button to Page Layout in Classic User Interface

To add a Conga Composer button or link to a page layout in the Classic user interface:

1. Navigate to Setup → Customize → [Object] → Page Layouts and select Edit next to the desired page layout. The Page Layout Properties screen appears.
2. Click Buttons or Custom Links.
3. Drag and drop your new button to the Custom Button area on the page layout.
4. Click Save.