Don't forget to ask them questions. Sometimes they don't answer but it gives you a chance to answer it and talk. I find things to talk about through things that I enjoy like listening to podcasts, watching YouTubers, reading things on Reddit, and mundane daily life things that I've observed. Keep talking topics in the back of your mind at all times to find things and make notes to remember if you have to. Don't be afraid to do a stream of consciousness of your thoughts (within reason). Talk about things that make you smile, happy, or laugh. If you're really stuck, then ask and answer dirty Would You Rather questions or sexy get to know your partner questions. Also, elaborate on your answer to draw out the discussion. There's tons of lists online! My tip would be to comb through them first and make a refined list because a lot of them are dumb, disgusting or repeats.
They'll pop in with a comment when they want to. Otherwise, they're just enjoying hearing you talk. Learning to talk with no responses is tough but necessary.