Help on where to start (am a beginner)

hellooo! i've never made a datapack before. i'm aiming to make a datapack where: if one person dies, everyone gets struck by lightning and then /killed then a few seconds later tped to the person who died then a title where it says in red "You Died!" and then another in gold that says "Score: X" x being the number on a certain scoreboard (will be the same for everyone so could just be any random player) where do i start? literally no knowledge, havent watched any tutorials or anything, i know minecraft command knowledge but not how to put it in a datapack.