While the Schema Builder is a powerful tool in Salesforce for visually creating and managing custom objects and fields, there are certain configurations that must be done in Object Manager rather than Schema Builder.
One of these configurations is enabling field history tracking.
* Field History Tracking:
* Field history tracking cannot be configured directly within Schema Builder. This setting must be enabled from within the Object Manager, where administrators can specify which fields on an object should have their changes tracked.
* Enabling field history tracking involves navigating to the object in Object Manager, accessing the field history tracking settings, and selecting specific fields to track.
* Limitations of Schema Builder:
* Schema Builder is useful for quickly creating custom objects, relationships, and fields, but it does not support all configurations, such as enabling field history tracking, defining object-level permissions, or setting advanced object configurations.
* For these types of configurations, administrators need to return to Object Manager where these settings are available.
Incorrect options:
* Add custom fields to the page layout: This task is typically done within Object Manager, but Schema Builder does allow customization of page layouts to a certain extent through drag-and-drop.
* Make available for Customer Portal: Schema Builder does not control portal availability; however, this is managed through Object Manager settings related to record visibility for portal users.
* Allow Reports and Activities: This setting can be configured in Schema Builder when initially creating an object, but further refinements and permission settings must often be done in Object Manager.
In conclusion, enabling field history tracking requires access to the Object Manager, as it cannot be configured through Schema Builder.

Explanation
To create a training sandbox with 160MB of test data that needs to be refreshed every other day, NTO should use either Partial or Developer Pro sandboxes. Partial sandboxes have a storage limit of 10GB and can be refreshed every 5 days. Developer Pro sandboxes have a storage limit of 1GB and can be refreshed every day.
Both sandboxes can include test data from production. References:
https://help.salesforce.com/s/articleView?id=sf.data_sandbox_environments.htm&type=5