This online manual from the Commission has everything you need to know about procedures from proposal application to running a project. There is also information on registering and working as an expert evaluator. Cross-cutting concepts important for projects also have a section.
https://webgate.ec.europa.eu/funding-tenders-opportunities/spaces/OM/pages/1867…European CommissionTypes of projectsEvaluation processDeveloping and managing the proposalDeliverables and reportingContract negotiationsWrap up / conclusionFinancial and legal issuesNewcomer resources0