How do you edit text screens?

I am creating a 1 Level WAD and I want to have a custom text screen at the end. How do I do this? I have a proper ZDOOM MAPINFO setup, so I just need to know how to do it from there? Thanks!

If I'm understanding properly, what you want to do is under MAP01 (or whatever), write "cluster = 1" and use the keyword "clusterdef" to define an "exittext".

Like this:

map MAP01
{
 next = endgame
 sky1 = YOURSKY
 music = music
 cluster = 1
}

clusterdef 1
{
 flat = F_SKY1
 exittext = "Write your text here."
}

Thank you!