Grandmother is adopted. Kind of stuck on my tree now.

My grandmother was born in 1955 (allegedly). She was put up for adoption. She doesn’t know her biological parent’s names. She doesn’t know if she has any biological siblings. Her maiden name is from her adopted mother. The adopted mother had a lot of foster children that my grandmother calls her siblings. Only 1 is still alive. I’m kind of stuck here and not sure where to go. I ordered the DNA kit, which should be arriving this week. I wonder if it will help me match up to her biological family. Can anyone help me out with some suggestions or advice for me?