The objective of HealthyCloud deliverable D6.2 is to lay out the specifications for a FAIR health data portal, taking into account findings from previous deliverables such as D6.11, D3.12 and D4.13. The key focus of these specifications is the compliance of data and metadata with FAIR principles in all aspects of the portal, from how the portal acquires metadata to how it models and presents it, to how the portal presents itself, both to humans consuming information directly and to machines tasked with finding and aggregating information on humans' behalf. The European health data space is undergoing rapid expansion and ensuring the long-term interoperability of health data while respecting the specific access an privacy needs of this context is a key challenge. A FAIR-compliant data portal that is able to expose harmonised metadata from a range of data sources is therefore an essential component for tackling this complex and multi-faceted challenge. In this report, we discuss the key requirements of the FAIR health data portal, in particular with respect to the features identified as essential in the deliverable D6.1 about user profiles. We explore the importance of a semantically interoperable metadata model and processes involved in bringing metadata from diverse sources into the metadata catalogue that lies at the core of the FAIR health data portal, with a view to building a central community resource that connects together and leads the health data space not just in terms of its data but also in terms of knowledge, guidance and research best practice.