Single-leg sled pushes and pulls involve emphasizing one leg to move the sled on each step, which is especially good if you're trying to focus on a weaker side.
An easy way to implement these single-leg sled push and pull variations is to simply perform half the distance or duration with one leg and do the second half with the other leg.
A lot of you have been training for years, and as such have experimented with dozens of training methods. Most are probably long since forgotten, like the girl with the braces and padded bra that you dated once or twice back in high school. There wasn't any chemistry and you went your separate ways.