Lunging a horse without a round pen can be done for beginners. First, choose a suitable area with enough space and a safe footing for the horse. Begin by attaching a lunge line to the horse's halter or bridle. Stand facing the horse's shoulder and extend your arm, signaling the horse to move forward. As the horse starts moving, stay in the center of the circle, maintaining a good distance from the horse. Use voice commands and body language to guide the horse. Start with basic lunging exercises and gradually increase the difficulty as the horse becomes comfortable and responsive. Always prioritize safety and make sure to end each session on a positive note.