Ask HN: How do you create product videos and screencasts?

Some examples: https://cdn.loom.com/assets/marketing/hero.webm https://a.slack-edge.com/5f6f2/marketing/img/homepage/hp-prospect/channels/bring-your-team-together-in-channels.mp4

As a dev primarily, I spent some time learning video editing over the past week. However it is not clear to me still how people create video like the above example videos to show the product and its features. Wondering how people go about creating / editing video screencasts ?