Welcome to the Bunnings Workshop community @Sere. It's fantastic to have you join us, and many thanks for your question about table leg fixings.
It will be helpful for our members when providing suggestions if you could upload some images of the glass top and legs in question. No fixings come to mind that will attach to the glass and screw directly into the legs, but I'm sure we can find a solution together.
I look forward to seeing some images and assisting with your project.