The first step is to tell the command-line tool how to access your account. You'll need the application key ID that you got when you created your account. Use the b2 b2_authorize_account command:

$ b2 authorize_account 07cd01a1cb39 
Backblaze application key: 
$

If you want to know what happened here, the command-line tool called the B2 service over a secure connection to validate your password and get an authorization token. The auth token is stored in the file .b2_account_info in your home directory if you want to take a look at it.

Now you can list the existing buckets in your account. If you're new to b2, there won't be any yet.

$ b2 list_buckets
$

Creating a bucket is easy. You provide the bucket name, and whether the access should be "allPublic" or "allPrivate". When the bucket is created, it will print the ID of the new bucket.

$ b2 create_bucket KittenPhotos allPublic
10f72c8d00b1ea614ceb0319
$

Now that the bucket has been created, b2 list_buckets will show its ID and name.

$ b2 list_buckets
10f72c8d00b1ea614ceb0319 KittenPhotos
$

Now you're ready to upload a file.

Warning: Do not include Protected Health Information (PHI) or Personally Identifiable Information (PII) in bucket names, object/file/folder names, or other metadata. Such metadata is not encrypted in a way that meets Health Insurance Portability and Accountability Act (HIPAA) protection requirements for PHI/PII data and is not generally encrypted in client-side encryption architectures.