This article will help you:
NOTE: Only customers who have purchased the Govern add-on (formerly known as Taxonomy) can initialize and plan the Schema.
The Schema contains the definition of the events, event properties, and event properties’ values collected by Amplitude. Use it to categorize and describe your event data, as well as automate the QA process for newly-ingested data by surfacing or blocking unintended or malformed data. You can even use Schema as an allowed-list of the event data you want Amplitude to collect.
Amplitude will collect and ingest event data that conforms to the Schema you've created, while violations to the Schema trigger notifications and will appear in the Schema violations view. This helps automate much of the data validation process when implementing new events or properties, and can alert you to corrupted or malformed event data.
The first time you open the Schema, you will have to initialize it before you can begin configuring it. Simply click the Initialize Schema button to do this. You also won't be able to plan events and properties before initializing your Schema.
After you initialize your Schema, you can then plan events and properties in the Schema by navigating to Govern > Plan Data. Next, learn how to plan events and properties.