As for the plan mechanics, it's all pretty straight forward. It starts slow, especially with the swim. Many people who start out in triathlon have a hard time making it across a 25 meter pool once. For others, this is a breeze. Know that we designed this plan for people starting from scratch. Change whatever you like to make it more challenging. And since when did you get all hardcore all of a sudden? The stuff here is for people just starting out. Take a chill pill, dude.
OK, swim distance is indicated in either y (yards) or m (meters). They're about the same. The bike training is measured in miles. Don't worry if you don't have a bike computer to tell you the distance. Before you head out on the bike, map out a route to determine the general distance. For the run, "m" stands for minutes - not miles.