If you’re a beginner, start with a weight that you feel comfortable lifting - it’s better to go too light than too heavy, especially while you get used to the exercise.
Once you’re comfortable with the exercise, increase the weight to a point where you can manage just about 8-12 reps.
Remember, lifting heavy and pushing yourself is how you can get stronger and progress in your fitness journey - as long as you’re putting a good amount of effort in, ultimately that’s all you need!
How do I set or change the weight for an exercise?
During the workout, before you start an exercise, you will see your sets / reps for the ongoing exercise. Here, you can set the weight you want to lift for the upcoming exercise.