A TRX routine for beginners need to be easy. You can ramp up the level of difficulty later on buy it would be best to start by mastering the movements and the system with simple exercises.
Consider executing the most popular exercises with the suspension straps. Do gentle bicep curls, squats, chest presses, and push-ups. Feel the difference when you are using your bodyweight instead of relying on a set of dumbbells. Notice the difficulty in maintaining stability.
Focus on controlled motions instead of heavy loads. Stay as close to vertical when leaning away from the anchor point to reduce the weight. Once you get comfortable, you can experiment with the angles to increase resistance.
You can also check online sources to get more ideas on how to use the TRX. It can be used to develop different body parts. It can even be used for stretching and stability training.