TV Shelf Question

Just received my TV shelf from TM. For anyone out there who has one, how are the L brackets used? I have the wall brackets similar to the ones on the hanging kitchen cabinet but also have some L brackets to provide extra strength. Do the L brackets stay attached to the shelf and just lean against the TM wall when you hang it? I plan to mount our shelf above the stove, as high as it will go so as not to be a safety concern.

Wade