The most important research you can do is on the bike especially outdoors. Ride and watch what it does. As you get some miles on these gadgets, and especially hill miles, you'll figure it out The PM tracks training, i.e. effort. The HRM tracks the physiological cost of that effort, and also the cost of past efforts. The idea is that having more data will enable one to make better decisions about what to do in the moment as well as what to do in the future. That means you have to have someplace to upload your data, tabulate it, and use it to predict future results. I use TrainingPeaks Premium, there is other, similar software. It takes experience to figure all this out. You can't do it just by reading, you need a body of work on which to apply these tools. So figure out what software you want to use and start using it.