To delete a component from an article, you need to open the article in the Studio Editor. In the next step you can click the component you want to delete. You will know that the component is selected when it appears in a blue frame.
You can now delete the component by clicking on the trash can icon in the bar at the top.
Don't worry if you accidentally deleted something or want to undo another change. You can undo your changes with the two arrow icons in the same bar.
If you have deleted an element, you have to save it and then publish the article again to delete the component from the website.