1. Backblaze will provide you the following details keyID, applicationKey and region. Use the keyID to fill in the key value and the applicationKey as secret value.
2. The endpoint URL depends on the region you've chosen to create your bucket, the endpoint can be found on your bucket page:
Make sure to add https:// in front of the URL when you enter it into the endpoint value so the above would be https://s3.us-west-001.backblaze2.com
3. Your endpoint URL includes a region name, in the above URL the region is "us-west-001". Use this as region value.
4. Then enter your bucket name as bucket value
5. And if you prefer to place all uploads in a separate folder inside the bucket then specify that location as path.