We will build a signature transition for a news portal. Actually, we will use a premade transition in the excellent magic library (https://github.com/miniMAC/magic), so you should add it to your project as a dependency. You can find the CDN link at https://cdnjs.com/libraries/magic (go to the page to find the link, don't copy it as a link).
First you will build the website page, then you will build the transition itself. Lastly, you will just add the transition to different elements.