Sort of, All the Components at the beginning of the Timeline - not wrong, but better to do each one as you need it,
Fusion will make it active at the creation, then you make the contents of the component. Each component as you need it, will sort a nice timeline to read. Near the end of the timeline, you may have to add something to a component - make sure it’s activated.
I am unable to access your file, (my end) so responding to the questions only.
Joints - usually you are moving something to a stationary component. You only need a common snap point in both of those components. Take the fridge, it has a rear bottom corner point. You join it to the intersection of the floor and a wall. (Corner?)
The dialogue box, allows you to Offset from the corner, in 3 directions. Set Offsets as required to space the air gap to the walls.
Common snap points - bodies, and Sketch articles that are in the component - are all selectable.
Orientation - the small joint disc used for selections - will always snap flush.
A good understanding of these three hints, Joints become easy.
Might help…
