Creating a Box Service Account and Box for salesforce

I am currently working with BOX and Salesforce, but I can't get a good connection.
When i try to set it up from the salesforce side.
Box Service Account:
Try again or contact your admin if error persists.
Only system administrators or users with "Box administrator" privileges can change Box service accounts.
Try again or contact your admin if error persists.
Perhaps the reason is that the box service account has not been created properly.
Is there a correct way to set this up?