@sallyb827 The correct angle slope is important with postural drainage, and it depends where your bronchiectasis is. Morning works best for me as mucus has pooled overnight and there seems to be more of it then.

Some have success with their bottom part on a sofa and head/neck supported by a pillow on floor. Or stack blankets on the floor. Or use the foot of an adjustable bed. Or inversion table.

Experiment with lying on your left, right and back sides. Personally, I find active cycle of breathing easier to do when inverted as it's a bit quicker than AD. If mucus is really stubborn try 2 vials of 7% sodium chloride in nebulizer before postural drainage proceeded by a bronchodilator. Avoid eating/drinking 2 hours before inverting yourself especially if you have reflux. Hope this helps you. It's all so frustrating!
https://bronchiectasis.com.au/physiotherapy/techniques/the-active-cycle-of-breathing-technique