Natural processes require time-localized, finite-time analysis, unlike traditional asymptotic approaches. This seminar will introduce methods for nonstationary oscillatory systems, including detection of directional coupling, transient synchronization, phase slips, and intermittent desynchronization. The MODA (Multiscale Oscillatory Dynamics Analysis) toolbox and a recently proposed time-dependent order parameter enable detailed analysis of instantaneous frequency synchronisation. These approaches provide a general framework for exploring complex interactions in oscillatory systems, with potential applications across physical, physiological, and ecological contexts, including ecosystems.