For how to display the Comment List, refer to the following.
30.7.4 [Comment List] Window
When [Target Item] is [Rung], double-click a cell in the [Screen Rung/Address] column to select the rung in the logic with the comment you want to delete.
When [Target Item] is [Variable] or [System Variable], double-click the cell in the [Screen Rung/Address] column. This displays the [Address] window and selects the relevant symbol variable or system variable.
Select the lower part of the [Address] window to select the target variable on the logic screen.