At most full-size cable parks, you'll start every lap from the dock. The cable runs at a fixed speed and can't wait for you, so the dock start is the single most important skill for getting on the water reliably. Nailing it turns the scariest part of a session into the most routine.
There are two common variants: the sitting dock start (you sit on the edge of the dock and get pulled off as the line goes tight) and the standing dock start (you step off with the board already under you). Start with the sitting version. It's much more forgiving. Move on to standing once it feels automatic.
Here is some more information:
Source: JB ONeill · HOW TO - DOCKSTART - SITTING - WAKEBOARDING
Key tips
- Start with the sitting version, graduate to standing
- Keep the handle low between your knees until the rope is tight
- Let the rope pull you. Don't lean forward or push off the dock
- Weight slightly back as the board touches water so the nose doesn't dive
- Look forward, not down at the dock
- Expect a few falls while you dial in the timing. Everyone goes through this