Initially the text was coded and organized into manageable categories that presented relevant and meaningful information. This phase contains the key steps mentioned in the previous paragraph. Fig. 1 presents the initial conceptual map of the relationships among the research ideas, categories, and key words that resulted from the analyses of all 1045 narrative responses (615 for design features and 430 for design guidelines). The key words were selected by considering the two research questions (RQ1 and RQ2). Words related to the key words were also chosen, for example, synonyms, and nouns, verbs, adjectives, adverbs, singulars and plurals with similar meanings. Based on these key words, seven categories were generated by analyzing the relationships among key words and the original interview data. A category is a word or phrase that describes an explicit segment of the data [79]. The major categories relating to the central idea of an enjoyable learning experience are the following: emotional descriptions, functions, designing concepts, techniques, learning subjects, learning concepts, and learning materials.