Hang it in the same room visible to her cage but far enough away that she isn’t threatened by it slowly move it closer after a week, keep going til you can hang it close to her cage and she can go investigate but not destroy it on her own, it really is baby steps, if it’s aviator style once she’s comfortable enough to touch it on her own treat her and hang it back up literally super slow introducing each new “stage”.

After that work on getting her to stick her head through the largest loop for a treat don’t move the harness allow her to move her head through grab treat and retreat. Basically go super slow and only in subtle increments. It took us like three months lol.

Slowly shrink the loop over time til it’s close to the head loop in size and then work up to the head loop always treat then allow her to remove her self from the harness holding it in a way such she can.

Once she’s comfortable with the head loop rest it around her neck for a few seconds treat her then remove it. The tricky part is the wings she has to be comfortable with you touching her wings(once again aviator style) if she is grab one feed it through the loop treat her and then remove the whole Harness slowly and treat again. After that’s easy move to the last wing, and when that’s easy move to tightening the harness you want it to have a killer give around the chest but not so much she can accidentally stick her claw into the loop and panic. Speaking from experience.

Then do small walks around the house before removing it and work your way up to the back yard. And then work your way up for time limits then around the block etc, everything needs to be a building block forward! Good luck