It is possible after I make one gig and have few sale on he to add a video ?! How ?! Thanks.
Yes it is. If you go to your sellers gig page. (“seller” drop down, “my gigs”) or for you http://fiverr.com/users/munteanu/manage_gigs.
Find the gig you would like to change video on after preview, promote, and show stats, the last option is “edit video”.