I'm new to the game myself and am trying my hand at edition.
If you just load and save the scenario it won't work because, as I understand it, there is no data base linked to the new slot and you have to, using the data base editor, load and save a data base to the same new slot number.
I've got to assume, since you jumped into editing on day one, your more up on the mechanics of playing the game then I am but, for what it is worth to anyone else, I kind of backed into editing.
To get the feel of the game basics I played the tutorial using the guide. On completing that plus going a bit past the ending point of the guide I felt that since I was comfortable with the very basics and what was going on in the tutorial it would be the best scenario to use to explore other aspects of the game IE supply, auto convoys, etc. Hence backing into editing.
I'm still on the up side of a very steep learning curve but with some very good guidance with the people on the forums I've found that between being able to more or less ignore the stuff I'd already got a handle on by completing the tutorial and being able to concentrate on the nuances using the editor I'm getting a far better insight into what is going on behind the scenes, so to speak, then I would have trying to edit a scenario where I did not already have an idea what obstacles the game and AI would throw up.