Top Down Modelling?

Hi Everyone.
Is there anywhere that someone knows of a tuturial, with spoken, “English” instructions on how to understand the Top Down Assembly design.
So far I can only find some tutorials on building from scratch.
I have over 7,000 parts in Inventor and after importing and saving some as ZW3D natives, I cannot seem to grasp the concept of how to use these in the Assembly, or multi File projects.
At the moment I have this front wall panel for a waste collection unit, attached to the sump panel and the rear frame attached at the other end of the sump.
What I need now is to create the rear panel that is basically a big rectangular plate with a cutout the same shape as the front wall, but 3mm bigger to permit the 3mm side plates to protrude through for welding.
I have tried creating the back panel with a new Datum point the required distance away, but after creating this, how do I then make the rear plate a seperate part for use in other models etc.
Any assistance would be greatly apprecated.
I am sure once I get the new paradigm down, this should be a great system. I would just rather not have to redraw all my components to make this happen.

Hi Russty,
I feel your pain.
Would you like a 1 on 1 Zoom lesson?
I could then use this session as the basis for doing a decent video on the process.
You might be surprised how many people struggle with the Top Down across CAD software.
Here’s the catch - my time Zone is NZ Daylight Saving.
You can send me a private message via the forum by right clicking on my identity icon and looking for the message icon on top RHS of screen.

Hi Russty, just thinking about this training offer, how would feel I I opened it up to first 9 others to join the Zoom meeting? e.g. You can pick a model that is not too top secret.

We get 40 mins om Zoom at the free level . It would be a good test for doing this kind of open training.


Hi Paul
That would be a great outcome.
What city are you in in NZ. I will look up the time on the magic google time clock and work out a time that would suit both of us.
Do you have a time that would be not practical or possible?
My schedule is chockers tomorrow, and a big mess in the middle of friday.
After hours is also fine, if that is what you need.
The image below is a component level of our superceded bin lifter system, just to give you some idea of what I am trying to accomplish.
I look forward to hearing from you.

Hi Russty,
there is only one time zone in NZ. My preferred time is after 6pm local time up until about 9pm finish.
I can do earlier times on a Friday and maybe a Saturday - if surf is not up.
Lets get a time sorted.