Transcription:This is copying down the recipe from your book onto another paper. In biological terms, it's creating an mRNA strand from DNA.
Translation:This is following your copied recipe step by step using ingredients until you get your final product - cake. In biology, it's synthesizing proteins based on mRNA sequence.
Gene Expression:The overall process by which information from genes is used in synthesis of functional gene products(proteins). Like deciding which cake(recipe) you want to bake.