Thanks Devin,
My next question is then:I how do I get to the URL address of my mp4 file (file stored on my computer)?
I tried using the “add media from the content file of layer#2, which allowed me to upload my file, then I copied the resulting codes and paste them into the “link” from layer#1, where is the object I want to link to the video.
When I visited the page and tried the link by clicking on the object, there was a “404: files not found” message.
Does it make sense?
Thanks.