[nradov]

You can register for a free NLM account to access the value sets (VSAC). HL7 standards are approachable for small teams but due to the inherent complexity of healthcare it can take a while to get up to speed. The FHIR Fundamentals training course is a good option for those who are starting out.

https://www.hl7.org/training/fhir-fundamentals.cfm?ref=nav

It might seem tempting to avoid the complexity of FHIR and CQL by inventing your own simple schema or data formats for a narrow domain. But I guarantee that what you thought was simple will eventually grow and grow until you find that you've reinvented FHIR — badly. I've seen that happen over and over in other failed projects. Talk to the CodeX accelerator I linked above and they should be able to get you pointed in the right direction.