I am looking for QGIS tutorials that cover the topics of making a user interface to update the attribute table or any related tutorial that might help. Does anyone know of one?
Have a look at the QGIS User Guide .
At the pages 129-130 (in the section 12.5.8 Working with the Attribute Table), you'll find all the user interface buttons you need to update the attribute table.
If you want to update the Attribute Table with Expressions, you'll find a complete list starting at page 110 (section 12.4 Expressions).