You will need to contact an admin from your organisation to book a private day office or meeting room if you do not have these assigned booking permissions.
You'll need to ask the admin of your account to either book this on your behalf, or allocate private day office/meeting room booking permissions to your account - they can also make you an admin so you can top up/pay for credits if you are on a Hubble On-Demand monthly plan. They can give you booking permissions via their admin page, here.
Your admins' name will be displayed on the booking page under the space you are trying to book and on the right hand side. You can also reach out to us and we can check your admins for you.