lost my file folders in thunder bird

[Doug Pollard]

This really dumb and the answere hs got to be simple. Clicked delete in 
the panel to the left of my mail  where folders are. I have clicked on 
about every thing in thunderbird and havent been able to get it back. 
been setting here looking for an hour. How do I get it back.  I can 
likely find the solution in help but I'm hoping for something quick in 
the way of help here. Thanks much,           doug