Emmanuel, Nothing happens, no message, yes online version

Can anyone tell me how to delete old plans from list. When I open folder to retrieve current plan to work on all previous plans now unwanted, are on list. I have tried high lighting and delete button without success.
Thank you for any assistance.

cannot find way to add new level, tool bar only says, new plan, open, save plan etc. when I look at video on how to do this it appears that there is a tool bar above the one I have described above. Appreciate any suggestions. Thank you.