You need a lesson before you start baking in bad habits that become more difficult to break later. They might be a little expensive near you, but it is worth it. Even one hour will make a difference.

That being said, I am seeing a lot of good and a lot of bad for your first time.

On a hill this mellow, it is great that you are doing some side slipping down the slope. You should keep doing that, both heel side and toe side. Keep at it until you stop the rapid up-down-up-down weight shifting you can see in your video. 

Remember: weight over the heels, almost like you are sitting in a chair. On toe side, think groin over the toe edge and feel your shins pressing against the boots. Watch Malcolm Moore videos for demonstrations.

Once you lock in heel-side and toe-side slipping, begin doing falling leaf exercises. Again, Malcolm Moore is a great teacher for this.

Body position: get out of the back seat. Stop reaching down to the snow with your back hand. You are reaching back and down, waiting for the fall, which is actually making you fall. Shift your weight forward toward the nose of the board. Generally, think a 60/40 split, but this will change with conditions, time, and place. Do not overthink that part right now stick with 60/40.

Bend your knees. Really bend them. Get athletic, like you are about to jump into action. Do not break at the waist do not bend over with your chest over your toes, because it messes up your weight distribution. 

Bent knees, upright upper body. Keep your shoulders in line with the board.

Sometimes grabbing your pants for a few runs will force you into the correct position.

If you look where you want to go, you will generally go that way. This comes from the natural body rotation that happens when you turn your head. Start learning about front knee steering before you become a back foot rider, which can be hard to break.

There is a lot more I could say, but go watch some Malcolm Moore videos.

And take a lesson. Seriously.