How to cut through component copies (repost)

[ittay.dror]

(Reposting since the previous one didn't include the screencast link and there's no option to edit it)
I'm trying to design a table. So I created a component for each plank, copied the number I need and tried to cut a recess for the leg (see recording link). But instead of getting one recess I get holes for each component. What is the proper way to create the recess? 
Here's the screencast: https://autode.sk/2Lzbzvw

[TrippyLighting]

Can you please share your design ?

[ittay.dror]

Here it is: https://a360.co/2Cw0cS1

[TrippyLighting]

I've created a screencast to explain tinges, but I am not sure it is particularly clear.

If not, please let me know.

[ittay.dror]

Yes, I understand all of this (and used mirroring to break the connection
in the leg), but was wondering if there was a les hacky way to do this
(other than mirror/copy). I gather not.

[TrippyLighting]

There is a way. Whether it is less hacky is another question, but it can be very useful.

If you create an empty component you can copy/paste the body from your seed component into that empty component.

Now you have 2 components with the same base geometry.  Any changes to either component after the copy/paste feature in the timeline will happen to each component and not affect the other.

Changes that you want to see in both components should be made to the seed component before the copy paste feature in the timeline. I've made a lengthy video a while ago about the copy/paste behavior of bodies an components in in Fusion 360.

This is the link to the handout for the class I co-hosted at AU University. It has a section called Configurations Light that describes the behavior.