From a forward fold take 1 leg back as far as you can.
Your hands are on the floor either flat or on finger tips (this will depend how low you can drop into the pose)
The front leg needs to be between the hands and the ankle and knee in line. The leg should be at right angle to the knee.
The back leg needs to be straight and your toes on the floor pushing back the heel toward the floor. This give great lenght and strenght to the leg.
You need to drop down the hip the bottom should not be in the air and you should feel it right in the groin and front of the leg.
Your looking point is slightly ahead but make sure there is no lift of the chin and the neck is straight.
The idea is to get the hips low and the back should create a long line from the heel to the top of the head.