You add instruments as you would any other item. They are associated with a specific layer and color. You can substitute the control valve or topworks after adding an instrument to a drawing. 
- What's New in AutoCAD Plant 3D
- AutoCAD Plant 3D
- Getting Started
- Interface
- Projects
- Collaboration
- P&ID Drawings
- Pipe Specs
- P&ID Line List
- Validation
- 3D Model
- Data Manager
- Isometric Drawings (Isos)
- Orthographic Drawings (Orthos)
- Vault Projects
- Report Creator
- Command Reference
- Content Notices
- Glossary
- Spec Editor
- Catalog Builder
- Manage Large Plant 3D Projects
- Subscription Benefits
- Installation
- Release Notes