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2. Create a Bucket Field on the file object
The Bucket field is defined on the file object, such as Account File, Case File, etc. We’ll use Account Files as an example here. This is a different field than the Bucket Id field that already exists on our out-of-the-box file objects (Account File, Contact File, Opportunity File, Lead File, and Case File) or that you created on your Custom File Objects.
Go to Setup->Object Manager->Account Files
Go to Fields and Relationships
Click New to create a new field
Choose what type of field it is, such as Text, Formula, Picklist.
Give your field a name (ex: Bucket To Upload To)
You can choose a default value if you wish, or you can choose to populate the Bucket To Upload To field on each file you upload
Once you’ve finished, click Save
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