Free mount
Getting on the wheel without a wall, fence, or friend to hold onto. Push the wheel slightly forward, step on with your dominant foot, then bring up the second foot as the wheel starts moving. That’s it. Takes most people days to weeks to nail consistently.
Why it matters
If you can only mount with a wall, you can only start rides near walls. Free mounting means you can ride from anywhere, remount after stops, and recover after stepping off at traffic lights.
The progression
Wall mount → brief wall touch → fingertip touch → free mount. Don’t rush it. The one-foot glide (riding on one foot while the other hovers) is the bridge skill.
555 take
Free mounting is the first real milestone. Until you have it, you’re dependent on infrastructure. Once you have it, you’re a rider. The how to ride an EUC guide puts this into the full first-week progression.