TOPIC: Medieval Mod (HELP NEEDED!!!)

So I have finally decided to create my own mod. It will be set in medieval Europe.
I still don't know what exactly this mod will include, since I don't have any programming experience and little to no modding experience, so this mod will be limited by my knowledge and abilities.
What it will include:
-Set in medieval era, with countries form that period.
-More provinces than current Europe campaign, probably around 150.
-Units will be modified to represent historically realistic units of countries, but the images for all units will most probably remain the same, since I am bad at drawing (also I don't know how to change them).
-You can choose difficulty not only by selecting it in the start menu, but also by choosing a country. Some countries will have weaker units than others, also some countries will start with only 1 province, while some will start with as many as 4 or 5.
-12 countries.
-Flags might remain the same in case I can't change them.

I will however need some help. It doesn't need to be any work, explanations and advises should be enough, since i have no programming experience, so I basically don't even know how to make this mod at this point (despite explanations given by ArDi. They are not enough for someone as inexperienced as me).
So, this is what I need to ask:
-How to draw borders?
-How to add new provinces? (I've already 'played' with the existing campaigns and deleted some provinces, but when i tried to add new ones, I couldn't, although borders remained)
-How to change unit images?

If I encounter another difficulty, I'll add them here.
Thanks to all in advance.
You are free to add suggestions, but I can't guarantee that I will actually add them- it will depend on my knowledge and abilities.

So I have found out how to draw borders, that's finished. The map should have around 140 provinces.
I now also understand what to do to change unit images and flags, although I'm pretty bad at drawing so I will have to find them somewhere and add them in a mod.
12 Factions have been added: Serbia (I had to add my own country, sorry ), France, Poland, Germany, Mongols, Byzantium, England, Fatimids, Castille, Seljuks, Sicily, Algeria
But there is still one problem I can't solve: Adding provinces. I read instruction several times, did everything according to them, but when I click to add new province, nothing happens. Is there something I missed? I need help about this one, I can't progress until I solve this

I tried to upload a map with borders, but it didn't allow me for some reason. I will upload a complete map once I succeed to add provinces

I have just found a way to actually add provinces, but now it crashed, giving me message :
ERROR in
action number 1
of Create Event
for object obj_controler:

Trying to draw non-existing sprite.

The problem is, when I loaded again, It kept showing me this message, and I can't continue.
Should I start over?

give me the map and i'll add the provinces for you, you'll have to name them and configure them on your own later though.

Sorry for being a little boring, I'm just new to this stuff and every once in a while a new problem occurs. I have solved this problem, fortunately, by deleting all files and info about 10 last added provinces. I finally understood what you told me, just clicking on provinces constantly, so by doing that I have finally finished adding them all. I had to delete some borders and add them again in paint, redraw borders, delete wrongly placed borders and few other minor issues, though, but it is finally over. Thanks for offering help anyway. And thanks for the advice.
Now I need to do few more things, and the mod will soon be over. I have a minor issue with unit and flag images since my drawing skill is just terrible, but i hope to solve this by copying images from somewhere else. I just need to find where it is legal to download such images.
I hope that this mod will be finished tomorrow, only those images might delay planned release. Screenshots will be there soon