Launch POIDE.EXE....
From the start bar click PellesC for windows -> Pelles C IDE
Click File -> new --> Project
Select your project type and a folder to put it in
Give your project a name
Click OK....
Now you're in the source code editor...
But don't stop there...
Click help -> contents
Start reading.
Pelles C is probably the best documented C development environment on the net.