The orange dot is telling you that your iPhone microphone is being used by an app. It'll appear when you use voice memos, maybe briefly after you close out of your camera, or if you're using any app that exclusively records your voice. The green dot is telling you that your iPhone camera is being used by an app. You'll see it when opening your camera, or taking pictures on Instagram, Snapchat, or any social media app that allows you to take pictures and post them.