Matthew Ibrahim walks us through the highly effective 1-Arm KB SLDL with the below steps.
1-Arm KB SLDL
1.) Tip your left foot slightly inward toward your right foot. This will help to avoid that unwanted external rotation of the left hip as we extend back, which saps energy and disengages the glutes to the extent that we want them at.
2.) Imagine there is a perfectly straight line from the top of your head all the down to the back of your left heel. Keep this line intact throughout the duration of the lift.
3.) A deadlift is a deadlift is a deadlift, just like a hinge is a hinge is a hinge. They are the same thing; therefore, treat the SLDL as you regularly would for a bilateral deadlift variation exercise. (Hint: Hinge!).
4.) Don't "try" to hit the floor with the bell. Just focus on your hip hinge, while contracting that left glute. Then, fire up back to the start position with that left glute.
5.) Run through all of those checkpoints prior to each rep in the set. Repeat on other side.
The movement can be seen here: