Slime usage with .lisp buffer?

I'm transitioning from 'mit-scheme -edit' (edwin) to Slime. I've installed Slime via MELPA and have the *slime-repl sbcl* up. I also opened a file C-x C-f 't.lisp' and the buffer shows only 'Lisp adoc'. Is this correct? I saw videos where the .lisp buffer showed 'sbcl'. Also, it appears I can evaluate the t.lisp buffer using C-x C-e with results, however am not sure if this is SBCL, Slime or some other method of evaluation. Does anyone know how Slime should behave with respect to a *.lisp buffer and evaluation? Thanks