Creating parent stuctures to organize parts to group them better. Is this possible?

Hello,

I have a file where they put together and there is no parent structure to organize parts. See below:

I want to organize these parts into three groups so it is easier to select and animate. I read about creating a parent structure or combining parts, but since there isn't much of a parent structure to begin with, I don't know if it will work. Everything I have tried doesn't change anything. Does anyone have any suggestions?

Sincerely,

Dustine