How Tarjei tracks training sessions and exercises

Here Tarjei Vassbotn shows his Tana fitness system. He tracks the type of workout, as well as his comments, feel, difficulty, and exercises. His exercises are tagged and organized as well.
This workflow can happen at multiple levels of sophistication. A slightly more advanced version would have tags for equipment, exercise types, and muscle groups. Then he could easily write a search to answer the question: "Okay I have dumbells and I want to work my triceps. What exercises have that?"