Does she like being brushed? We have lovely brushing sessions with ours, she loves to be brushed - now I can trim behind ears no problem, but when she was a puppy she would freak out.
We eventually got there by just doing the ears very slowly, with lots of brushing (that she enjoys) all over her body and on ears too.
Keep the scissors and comb nearby, do a nice relaxing brush of the ears, brush brush brush until she’s got eyes closed, and then go in and trim a bit of the knot. Brush some more, trim a bit. Brush her paws/tummy, head back to the ears and trim some more.
Make sure you’re holding the skin between thumb and forefinger to ensure you know where the skin is at all times and don’t accidentally cut it.
Cut into the dread as much as you can, and then brush out the rest.
Stop if she gets bothered and try again the next day.
Get a few different brushes for the job.
We have one called a coat king brush which takes the fur and is great for breaking up the behind the ears knots. Trim off as much as you can and then use the coat King on the rest.