Ok...new to game. Need help.

You have alot to learn my young padawan.
To make the perfect nation/empire you would have to use holy wars or conquest wars and then give land to people of your religion and culture to avoid negative opinion modifiers.
And as Apulia you should probably swear fealty (not sure if i spelled that right) to someone bigger such as italy or the byzantine empire. Or maybe try and get a alliance through marriage with byzantine empire if possible.

Another great advise is to save up 300 gold and never go below that so you can always hire mercenaries when need be.

If you have "the old gods" expansion you should start as the petty king of svitjod. The good thing about that is that pagans get subjurgation casus belli if they pick the ambition to become king of [insert formable nation here]. So the petty king of svitjod can quickly unify the swedish lands.

As for France rebellions are your friend since your kingdom become more stable after you win and replace the imprisoned vassals with vassals of you culture.

CK2 will continue to kick your teeth in until you learn the mechanics Wiki and youtube have alot of information though. So that makes google your friend.

Until you break 100 hours, you are still a novice. At almost 300, I am only beginning to understand.

As for the advice to pick Svithjod, that is a good choice, but I would go for Harald Fairhair (Norway). He doesn't have any brothers who keep dragging him into wars in England.

If you're starting in 1066, Ireland or Spain is a good starting place to learn some of the warfare basics. Skip Ironman for now, so you can save/reload and experiment.

Pause the game frequently and make sure vassals are happy. Keep them out of factions to help prevent civil wars. Lots of ways to do this: wards, bribes, feasts, council, etc.

Keep your tax revenue up and always keep enough in the bank to hire mercenaries if things get dicey. Try to get a strong alliance or swear fealty if you're a little fish swimming with sharks.

Don't play nice, these were warrior cultures where conquest was expected of a great leader. Play for power. Put those ambitious dukes in prison when they plot against you, and don't be afraid to be a tyrant if everybody already hates you anyway.

Civil wars doesn't mean you lose. It means you're playing as intended by the game and the devs.

Players that never see civil wars against them in their blobby realms aren't playing the game, they are skirting it.
I have currently 1423 hours in game, and for a time, I thought that the goal of the game was just about expanding and trying by all means to keep the vassals happy... even if it means using exploits. I was wrong.

Now, of course, you ave to win some of those civil wars. But it's not bad if you are reduced to a duke for a time.

If your getting this many civil wars consistently it sounds like you don't full grasp how to maintain your internal politics, improve relations, gifts, honorary titles, imprisoning vassals if you have a reason to just so you can release them, stack prestige, marry relatives to vassals and those are just the basic ways to deal with it

If there are serious problems you can make vassal kings, it will give you a fiercely loyal vassal at first although could cause long term problems or you could plot to kill some people, and get children for vassals instead but if you get hit some of plot revealed events you could have more trouble, may it be noted never spend the money to assassinate people to fix internal issues, frankly if you have the money for assassination its better to just spend it on mercenaries and win the civil war that way

I have held together large realms with rather bad characters by such tactics.

Maybe you should try playing as something more remote, Ireland is a classic area to play, its safe and easy at start but isn't completely lacking in challenge especially if you wanna take all of Britannia and depends on your start date you will either have to deal with united England or Norse invaders both offer their own challenge

I would also suggest being someone's vassal, a duke in any large kingdom or empire can be decent, going from a duke vassal to an independent kingdom is always a fun journey