To add a new supplier into Tern, follow these steps: 1. Go to the Itinerary tab within your trip. 2. Click on the item where the supplier should be added. 3. Use the type-ahead search to find the supplier, or create a new one if it's not listed. 4. Click "Create" and fill in property details such as name, website, and location. 5. Click "Save" to finalize and add this supplier to your itinerary and our library. The information will then be available for future proposals and itineraries.