I can't answer your question but I notice you used a camera to record your actions in SE.
Do you have an icon in the lower right corner of your SE window like shown here:
You can click it and record your SE session, save it, share it.
In the Parts Library, try to rotate the model in the preview panel at the bottom using the middle mouse button or scroll wheel before dragging it into the assembly. After dropping the part, also Zoom Fit the view.
Also, does the part name show up in the Assembly tree ?
If yes, right-click the newly inserted part and select Show-Hide component and in the dialog,
Then check ON Surfaces in the dialog that appears.
See if all this helps.
Regarding the recording ICON, yes it's there...just the client didn't use it. I will ask client to use it later.
The issue is after bring the part into the assembly, the PC stop from working. Nothing can be click except the close window icon.
So I can not do right click to show/hide component in assembly.