After selecting the ‘Entity’, you can add the Field using Columns or FetchXML query.
If you select the Columns, you will get the Fields (including standard & custom), drag & drop the required fields from right to left to add the columns for the list.
From the Field Configuration, you can edit and update the title of the field.
After updating, the Field labels click on the Save button and finalize the list builder by clicking on the Publish button. You can keep it as a draft by clicking on the Save As Draft.