The phrase "to warm the atmosphere" means to create a more friendly, welcoming or comfortable environment through actions and behaviors that make people feel relaxed, happy and at ease. It can involve things like being hospitable, making others feel valued, showing kindness and empathy, creating an inviting ambiance with lighting, music or decorations, using humor to break the ice, etc. The goal is to create a sense of connection and rapport among those present, so that they feel comfortable expressing themselves and engaging in conversation or activities together.