Best method to record A/V instruction for the Storyline eLearning that I made?

Hi All ~ complete newbie here. What's the best method to record A/V where I'm giving instructions and narration on the actual Storyline eLearning that I created? To make this audio/visual capture, do I have to use a different method or can Articulate do this for me? If it's another method, which software is recommended? Ideally free? Could be Zoom Clips? I'd like one that will seamlessly allow me to toggle between full screen video of my speaking, then put my head into a small circle at the bottom corner of my Storyline training 'deck.' All suggestions are greatly appreciated!