Step 1: Define a Platform Event

Create a custom platform event named Order Event. The steps in this quick start use this platform event.

From Setup, in the Quick Find box, enter Platform Events, and then select Platform Events.
On the Platform Events page, click New Platform Event.
Complete the standard fields, and for the description, enter Example event for the Pub/Sub API client.
Save your work.
To add a field, in the Custom Fields & Relationships related list, click New.
Follow the custom field wizard to set up these fields.
- Field label: Order Number (API name: Order_Number__c), field type: Text(18)
- Field label: City (API name: City__c), field type: Text(50)
- Field label: Amount (API name: Amount__c), field type: Number(16,2)