to your first question
open your project
make sure you are using project view mode
click add new in the files box
type the file name of the source file you wish to add into the dialogue box
click save in the dialogue
then save all in dark basic pro
to get to your main file, double click in the main source file box
to get to your added files, double click on the name of the file in the include files.
however....
inlude files are still not full proof
if you get a bug in your program it will point you to line numbers that do not exist.
make sure you click save all before you close dark basic pro otherwise you will loose your sorce files
hop this helps
I have a word of advice...
..don't piss on an electric fence!