It all starts when they are very young. I get them playing a game around my feet on grass just long enough for a ball to almost disappear in to when dropped. Lots of repetition and they soon learn the game of hunting close to find a ball. Then move to ground with scent on it so there's something natural to get them interested and then keep progressing
I done far to much early retrieving with Harry so to encourage his hunting I didn't restrict him and he now take more ground than I would like. I'm at a stage with him now that if he fails to respond to a turn whistle then I'm out on his case giving him plenty of verbal. It's not easy has he can be bloody minded when he thinks he knows better.
One you first video above, you throw the dummy over the dogs head and she get up and turns around. I'd have gone and put her back and collected the dummy myself. I'd then have repeated the exercise again. At this stage your wanting 100% compliance with what you've asked for.
Sit her up so she's looking at you. Throw the dummy over her head, it's not a problem if she looks over her shoulder but you want her to remain sitting looking at you. You can now use this to build to a get out vocal and hand signal. Once she's happy you can put more distance between you and the dog then build to calling her towards you, stopping her half way as she comes back to you and then sending her back.