This document proposes and describes guidelines for the annotation of music structure into elementary units called semiotic blocks, reflecting high-level and high-scale similarities across the music piece. The annotation process requires both the localization of block boundaries (segmentation) and the determination of block classes (labeling). The proposed methodology is based on concepts and principles inspired and adapted from semiology. It combines elements resulting from the analysis of internal properties forming systems within blocks (morphological analysis), from the characterization of distinctive properties across blocks (paradigmatic analysis) and from the location and context of blocks within the music piece (syntagmatic analysis). The implementation of these principles has resulted in a set of notations which are also developed in the document.