Hello, how can I delete the field "sample logo" above?

Here is how you can remove that logo:

1) Click on the Form Designer icon.

2) Scroll down and click on the Advanced Designer.

3) Once on the Advanced Designer, click on the Form Cover tab.

4) You will see the image field, there click on Remove button.

5) Save the change, and go back to the builder.

Let us know if you need more help.