Find a hard surface to lie on. You won’t find maximum benefits if you lie on a bed, as tempting as it may be!
Elevate your head. You’ll only need a book or two or perhaps a rolled up towel or blanket to elevate your head just a bit. This will help you find the sensation of letting the back fall away and deepen into the ground.
Bend your knees and leave your feet flat on the ground. You can feel free to be barefoot, wearing socks or shoes even. However you are most comfortable.