Can you share your model and perhaps explain what you are expecting to see ?
I see what you are doing in the screencast, but I am not sue I understand what is going wrong.
Looking at your file now. One piece of advise, after importing geometry wait with enabling the timeline until you have all the geometry cleaned up and stitched together and maybe the assembly re-structured.
Only then enable the timeline if you must.
That way your timeline is not cluttered with a lot of operations not relevant to the actual design.