I’ve heard Patricia Walden, one of Iyengar’s senior teachers, call standing poses friends for life. I believe warrior 2 or virabhdrasana to be one of those key standing postures that one will always return to in their practice.
This pose is difficult for beginners to get into completely. Having their bent leg at 90 degrees takes time and strength building in the core and legs. The further the legs are apart the more work done my muscles to hold the pose. If you find it difficult keep good foot posture but decrease the distance between the feet. Always keep the knee above the ankle, none of that moving it out in front.
The second most common problem I see for people in warrior 2 is they don’t open their hips. This was a revelation to me when I was first shown, I’d been almost completely unaware of my hip positioning in the pose previously. Both legs are opening out and stretching apart through the hips. Both legs are turning out so that there’s some focus on having the outer or pinky toes ground into the floor. Most people will sag through the hips and sag through the shoulders. As I often tell my students, “No one slouches into battle! Hips open, shoulders back and down, open the chest.”
As you gain strength increase the distance between the feet. Warrior 2 makes a good transition into triangle pose or trikonasana if the feet are closer together than I have in the video.