1) Show Comments panel by going to View -- View Settings -- Navigation Panels
or clicking Comments icon on the left side toolbar.
3) Select comments that you would like to delete.
a. click anywhere in the Comments panel and press Ctrl + A to select all comments
b. hold down Shift and click on the first and last comment to select all
c. hold down Ctrl and click on the comments you want to delete one by one.
4) Right click on anywhere on the highlight area and click Delete.
