Opening multiple windows in a screen from a detached state.

I am trying to automate the process of running, in parallel, every
file in a directory in new windows in a new screen session.  The
portion of this I'm missing is the ability, from an attached state, to
open a new window and name it.  I think this might have to do with the
screen "screen" command, but I can't find any working examples of what
I'm looking for, and it's incredibly difficult to google that term.

I can get as far as:
screen -D -dmS practice -t first

That opens a new screen session and names the first window from the
outside, in a way I can send commands to (which is "-X stuff
"command"" I believe), but I don't know from there.

Thanks in advance, help is very much appreciated.
--David