The FOI exemptions take many different forms:
There will often be scope for more than one exemption to apply to information which it is not in the public interest to release. You can cite more than one exemption when responding to an information request if you decide to withhold the information.
You must of course ensure that each exemption relied upon is satisfied on its own terms.
There are however some very specific provisions within the Act where it is not possible to rely on two exemptions at the same time. For example, section 36 (prejudice to the effective conduct of public affairs) expressly states that it only applies if the information is not exempt under section 35.
These interrelationships are explained in the individual chapters of the Freedom of Information: Exemptions guidance.