From the global search box, you can start typing the word "skill" or you can click on the Settings page in the upper right hand corner and under the Programs section, click on Skill Levels to get to the Skill Level Management page.

Click the "+" button, type the new Skill Level name you want to add, and press "Save".

There is a list of Legacy Skill levels that are preset in the system. You can choose to inactivate any that will not be used by your Organization by pressing the toggle button next to the Skill name. The form will autosave.

To edit an existing Skill Level, you can click on the name and make the change.