This PDF is the Simple SES guidance created in the Marine SABRES project. This guidance document centres on the use of overarching and individual Standard Operating Procedures (SOPs). To navigate this guidance document, the user should begin by reviewing the two overarching SOPs which together provide a comprehensive overview of the sSES: one covers the Process and Information Management System (PIMS), while the other details the Integrated Systems Analysis. This approach will provide end-users with a structured procedure to analyse complex marine management issues, using the DAPSI(W)R(M) cause-consequence-response framework and systems thinking tools to reduce the perceived complexity. This approach includes creating causal loop diagrams that visually represent relationships and feedback loops within the system, and which in turn can be used as communication tools to enhance understanding by, and engagement with, relevant actors. The approach facilitates identifying data gaps and encourages the use of various data sources, including scientific data, local knowledge, and expert judgment. Moreover, the approach supports stakeholder engagement throughout the Simple SES process, promoting collaborative decision-making and shared ownership.