As erwinkle mentioned, these animations use anime.js
If you want to build something but don't really know how to do it, I would suggest the following:
1. Build the visual content in an SVG with Inkscape. It should be easy for you to build the layout with assets/item to animate. Don't forget to group items and set names so you can reference them later.
2. Once exported, insert the SVG in an HTML page and add anime.js. This library will let you animate the content you just created (you should be able to reference your named items from Inkscape and animate them). The learning curve might be tough depending on your experience regarding animation (or CSS in general).
1. Build the visual content in an SVG with Inkscape. It should be easy for you to build the layout with assets/item to animate. Don't forget to group items and set names so you can reference them later.
2. Once exported, insert the SVG in an HTML page and add anime.js. This library will let you animate the content you just created (you should be able to reference your named items from Inkscape and animate them). The learning curve might be tough depending on your experience regarding animation (or CSS in general).
Good luck :)