Just to expand. The stash is exposed to the template at the top level (by default, in TT views, not necessarily in all views) so these are equivalent-
[% Catalyst.stash.foo %] == [% foo %]
And unless you're using the TT::Site view helper/generator or have modified your CATALYST_VAR yourself in your view configuration, then c will be the default Cat context/app object-
[% c.stash.foo %] == [% foo %]
I have mixed feelings about using Catalyst v c in the templates. It's nice to be explicit but at the same time it crowds template code and if one can get used to $r in modperl, c seems fine.