By default it should open to "All Media". From here you can view all the files you have uploaded in your instance such as images, documents, and videos.
This will open your folder for you. In this case I wish to rename the "Brand" folder.
This will trigger a drop down with multiple folder options.
This will trigger a rename modal.
In this case, I am renaming the folder "Brand" to "Brand Assets".
You can see the new folder name in the header!