If you don’t have a birthing stool use a low set stool (child’s stool or a 3 legged stool)

With your partner sitting behind you with their knees around you lean backwards, use a pillow folded up at your lower back if necessary. While in the supported position lift one leg and keep it raised on a step or on a few large thick books. This tilts your pelvis and aids babies descent into your pelvis.