This is such a beautiful pose, and when done with the wheel, can feel oh so nice on your spine. Tips for getting into position:
1. Start by sitting in sit-up position (feet forward, and knees bent upwards in front of you), while holding the wheel at the back of your neck with both hands.
2. Slowly sit back until the wheel makes contact with the ground. Keep hands in place, and slowly roll backwards. The key here is keeping the body as straight as possibly while rolling. Actively draw your shoulders away from your ears and towards the tailbone. This will loosen the shoulders and neck.
3. Place elbows in a right angle above your head. From here, you can walk the feet in closer for a fuller wheel-pose stretch, or keep them outstretched. One advantage to using the wheel in this pose, is you don't necessarily have to hold the pose once you're in it. Many users enjoy slowling rolling back and forth with it to relieve spinal and muscular pressure. Listen to your body, take things slow, and do what feels right for you.
Happy rolling! Feel free to share any of your own tips/methods in the comment section!