@Anonymous
Have you been through any of the tutorials in the support and learning section?
You made so many mistakes in this simple design that I would recommend to spend some time there to get the upper hand on some of Fusion 360 fundamentals.
I would stay away from the primitives especially the box primitive in Fusion 360.
When you created the rectangular sketch you should have picked the sketch origin and not place the first point of the rectangle into space.
When you do that your geometry aligns automatically with the origin. Keep it there! When I refer to geometry I refer to the body in a component, not a component. That way you don't need the body move feature to move it back to the origin. Saves some unnecessary work.
In your second step you scale that body. Not a good idea. You are in a parametric modeling environment. If you need to change the dimensions of your geometry, then edit the sketches and timeline features it was created with.
That also works better when you don't use the primitives 😉
Then you copy paste the cube component multiple times. It would have been a lot easier to pattern this and then remove (not delete) the unneeded instances.
The dimension of the cube is a parameter that is stored. You probably better define a user parameter and assign that to the dimension of the cube (well ... three dimensions). Then you can also use that parameter when patterning. So when you change the dimensions of the cube the pattern updates accordingly.
Then you can use a rigid group and things will update properly. In your design you manually moved the components and that does not work update when you change the dimension o the cube.
The biggest faux pas you made with the last move command in the timeline where you moved the body of the cube away from its origin in the component. That is almost never a good idea unless it was intended for a particular purpose. I don't think it was intended in this case.
This is also the reason the joint icons show up toward the side as they coincide with the origin of the component. As build rigid joints and rigid group don't require to select geometry so they reference the component origin.
