The Spanish universities as a whole, together with the Spanish Ministry of Education, have reached an agreement that the UNED (Spanish University of Distance Education) will be the institution in charge of verifying and giving documentation that Ukrainian students may have regarding their studies. Therefore, they will have to contact the UNED to start the verification.
The UNED link: UNED: https://unedasiss.uned.es/home
And the addresses in the Valencian Community: https://unedasiss.uned.es/convocatorias
Once the UNED has issued the documentation that accredits the studies carried out in Ukraine, you can pre-enrol in one of the Valencian public universities:
Valencian public universities: Deadline: from 20 June to 8 July.
Application: https://appweb.edu.gva.es/preinscripcion/