Log in as a Teacher on Skolera LMS.
Through the Navigation menu on the left.. Press Courses > Course name
Select the required Class 

Select the Gradebook Tab
Click on the tab <Edit grade item> on the upper right side
A list of all created Grade Items will be displayed.
You Can Delete a Grade Item by Clicking on Delete
You can easily edit a Grade Item by clicking on <Edit>

Kindly note that you can't make changes to the assignment / online quizzes columns that are already created on the platform ,to make changes , refer back to the course level.