Beginner going for the dumbbell workouts

HI! I'm new to FB and I'm just wondering what weight of dumbbell should I buy for the workouts? I was doing the no equipment workouts for now but I also want to try the workouts using dumbbell. Really want to know that is suitable for beginners to lose weight. Thank you!

Thank you for all of your suggestions/advice especially since I'm just starting out. Thank u!

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