As just mentioned, binding decisions are a new instrument in the GDPR. They are the subject of a second graphic from the European Commission, depicted below, which further elaborates on the one above and is part of the same EDPB factsheet as the Commission published it in January 2018.
The binding decision is subject of GDPR Article 65 which explicitly covers dispute resolution by the European Data Protection Board in case of conflicting views and disputes on the levels of DPAs and lead DPAs. Article 65 explains how this conflict resolution works and what the process looks like (again: it is for the EPDB).
The graphic shows how binding decision making by the European Data Protection Board looks like in practice, summarizing Article 65 and taking similar data protection issues in several countries (for which there are cooperation rules and mechanisms for consistency and more) as an example.