Please help! Struggling to Sew Ruffles!!

Hi all,

I’m attempting to sew ruffles for the first time and currently getting really frustrated as a beginner. I put some basting stitches in and gather their the ruffles until I was happy with them.

However, when I went to sew back over the ruffles, I realized that my presser foot is just flattening them back out and loosening the basting stitches.

E.g. they go under the foot ruffled and come back out flat.

What am I doing wrong? Is there a way to adjust the height of my presser foot while sewing? I wasn’t able to find anything on this elsewhere, any advice would be greatly appreciated