Front balance typically refers to the position where your whole body is balanced on the front of your hips on the bottom bar of the hoop. The exact positioning might vary depending on your proportions, similar to back balance.
I think people most often use the name to refer to the position where your body is extended (legs up and straight, back arched and head looking up – similar to a locust position in yoga on the floor). It can also be used to refer to other variations, such as when you’re folded in half over the bar.
The easiest version of front balance allows you to use your hands on the hoop. As you get more confident, you can start taking them off. Keep in mind that having your hands by the side or in the front will alter the balance point.
A common (but not easy) way to enter this pose is through a pull over. Begin by standing on the floor with your hands on the bottom bar in the chin up position. Then lift (or jump, when starting out) your legs through the hoop until your hips land on the bottom bar. For an easier version, you can use your feet on the sides of the hoop to help you shuffle over. Here’s a demonstration:
You can also enter from seated by flipping yourself over in various ways, or from a hip hold by moving the flying leg through the hoop, etc. Exit by reversing any of these approaches.