Reminds me of the first time I tried a closed split tail. How the heck do you get off the ground? (I said to myself) Getting off the ground is the trickiest part of climbing a closed split tail.
Remember that it is a completely different paradigm than climbing on a Blake's. You don't really advance the hitch. The rope just moves through the hitch as you go up. You advance yourself, not the hitch.
A few comments about your setup. You have too much play in the system, see how the biner holding the hitch drops down the bridge? You want that biner to stay in one place. Three ways to do it on your harness:
1. Put a swivel on the bridge and clip both biners into the swivel
2. Get a hitch climber pulley
3. Put a ring on your bridge that's large enough to attach both biners
What happens either way is that the biner holding the hitch is anchored and won't go sliding all over the place when you stand on and pull down the rope.
Another place to remove slop (play) is to shorten your hitch cord so there's just enough to tie the hitch and get it on your biner. Feel free to add a little more tail on the scaffold hitch, you don't want that to slip through.
After you get that tuned up you'll have a chance. You'll need to hand tend the rope through your footlock to get off the ground. It's a little awkward but you have to do it until the weight of the rope takes over and tends your single footlock loop. It is much easier to use a Pantin. The Pantin starts self tending very quickly, for my rope (Tachyon) it's when my Pantin foot is around 6-8 feet off the ground.
Other problems you may encounter...
When you have the working end of the rope (up rope) and the hitch biner in close proximity (on a swivel, the same ring or a hitch climber pulley), the double overhand loop knot (Scaffold, whatever) can cause the hitch to release. That's one reason why most climbers like to have a splice on at least one end of their rope. The splice won't upset the friction hitch.
The basic climbing principle is...
You don't advance the hitch, as long as you're moving up (standing on the rope with Pantin or single or double footlock on the tail and pulling down with both arms above the hitch) the hitch just sits there and the rope passes through it. When you want to stop to rest or you've reached your destination the hitch grabs the rope. Depending on what hitch you're using and how long the split tail is etc. you may have to flick the hitch up from its "collapsed" position to make it grab. That' show the hitch is supposed to work, when you're climbing it collapses, when you load it it extends up and grabs the rope. Whenever you load a closed split tail to set the hitch you have some "sit back". The more play in the system, the greater the sit back. Most climbers try to remove as much play as possible from the system to minimize sit back. If you have way too much play you're not going anywhere (what happened in the video).
If you can find a local climber who uses a closed split tail hitch it would be very helpful to examine their set up and observe how they get off the ground.
Caveat:
Many work climbers don't climb from the ground on a closed split tail. They footlock on a doubled rope or SRT up, then switch over the DdRT closed hitch once they're in the tree.
There is also the hitch bridge system that basically puts your hitch biner on a tether and allows you to get off the ground same as you would on a Blake's, pulling rope below the hitch. Once you're in the tree you move the hitch biner closer to the harness (still attached to the tether) and then take advantage of a closed split tail for climbing in the tree.
Hey, you should've asked at Tanglewood! I would've shown you

I put a Pantin on my right foot and single footlock the tail below the Pantin with the other foot so I have two legs working instead of just one. As I mentioned you can also footlock the tail with both feet to get the same effect
-moss
PS, I accept donations
Ps 2: I just noticed that you do have a spliced eye on the climbing rope, on eless thing to worry about.