Welcome.
Well, first of all: look at the "Forum Rules, Gp3 FAQ..." section: you'll find a lot of tips about editing, very clear and useful. A must.
Second: look at this forum topics, many of them are about editing, even for beginners.
Third: if nothing work, probably you don't have the decrypted Gp3 1.13: you'll easily find it both in the new and old dowload section, after you have learnt enough about editing, of course.
About Gp4 i don't know, as i don't have it.
Bye.