First you will need to access your website editor. If you don't know how to do so, you can read this article
Next, you will need to access your front page editor. If you don't now how to do so, you can read this article
To delete widgets, once you are on the front page editor you will hover over the widget and select "Delete" as in the picture.
If you wish to delete a row of widgets, in the top right of the row, there is a wrench which you will hover over and will select “Delete.” It will ask twice if you are sure you want to delete that row.
Once you have deleted the desired widgets, on the right side of the website you will press the "Update" button to finalize these changes.