Sitting half lotus forward fold

Technique

Sitting with legs extended, bend the right knee and bring the right foot to rest on top of the upper left thigh with the sole of the foot facing upward.
Hinge at the hips and fold forward, reaching both hands to hold the left foot.
Lower the head and take 5 breaths.
Sit up, switch legs and repeat on the other side.

Half lotus can be difficult for those with knee issues or tight hips.
It requires a substantial external rotation of the hip in order for the foot to come into the opposite hip crease with the sole facing upward.
Also, the knee joint needs to be able to close all the way to prevent it from taking too much sideways pressure if the hips are not open enough.
Good prep poses for half lotus are Butterfly stretch (baddha konasana) and firelogs pose.
Go slow and be patient. If half lotus doesn’t come easily to you, it is recommended you work with a teacher.
If your foot is to the top of the thigh and everything feels fine, bring the knee forward (toward the opposite knee) and continue to rotate the upper leg externally as you tuck the foot deeper into the opposite hip crease.
If folding forward puts pressure on the knee, continue sitting up and support a straight spine with the hands beside the hips.