Within this manual you will find a descriptive guide to the MHINT coding procedure, general rules for coding, and detailed descriptions of each ‘behaviour group’ with illustrative examples.This manual aims to capture as many relevant behaviours for the evaluation of an interaction as possible, with the underlying hypothesis that individual differences in behaviours can occur subtly and that micro-behaviours are of great importance because they provide specific targets for intervention.The coding scheme can be applied to footage obtained from video cameras installed in the home, those used by an observer, or as in our own research, through wearable headcams and a ‘spy’ photo-frame video camera (Lee et al., 2017). Combined, these methods give the observer the opportunity to code behaviours from different perspectives and, interestingly, to obtain the perspective of the participants. The advantages of this approach are explained in Lee et al. (2017).For ease of use, this manual has been divided into five different sections: perspectives, independent variables, subjects, behaviours, and modifiers. To begin, each of these terms is defined.