Have you ever wondered how heavy all objects in our Milky Way are together?

Weight and mass outside of Earth are tricky. You can’t just put planets, stars, or other space objects on the scale. Generally, when you’re on a scale, it measures how hard the gravity of our planet is pulling on you.
On Earth, you weigh a certain amount, but if you could teleport to Jupiter now, it would be different. So, how did the scientists manage to weigh the Milky Way?