Almost all of the stars we can see in the night sky are members of the Milky Way Galaxy. The brightest star for us is the sun, and it is a long way away, 93,000,000 miles. The next nearest stars are thousands of times further away. All of the stars are moving, but they are so far away that they appear to be standing still relative to each other. (This is also the reason why it looks like the moon follows you around when you are riding in a car.) The patterns they form in the sky are a complete accident that depends on their locations compared to each other, and on our position on Earth from which we see them. Some constellations are made of stars that are not even very close to each other! So the trick answer to your question is that stars don't make constellations, people make constellations up from the random arrangement of stars in deep space.
One of the special things about constellations is that we see stars as being placed on a surface like the inside of a bowl. But stars are really widely spread out through space. There is no bowl.
Try this: Place four or five small items all over a table at random. Erasers would work well. Now stand back several table lengths, stoop so your eyes are level with the table top, and close one eye. Can you see that the objects look like they are all in a line?
