I know when you are in a man page it will display the file name at the bottom inside the man.
How can I do the same thing manually?
I'm not sure it is possible to do everything you ask, because
man(1) sends the formatted man page data to your pager program via a pipe. This would prevent showing a file name, for one thing.
You can get a line count at least like so:
PAGER environment variable to
-M to your
LESS environment variable, to get the "long prompt", which includes the line count.
-M, you can build your own
less prompt with the
-P option to get even more details. Again, though, there are some things in what you ask that
less simply won't have access to when acting as
man's pager program.