Thanks for the links. I've read trough the book. Very hard to understand for someone that doens't know alot about football tho haha. But I hope my knowledge will improve while playing the game.
I'm going to start a new save with MAN UTD. Since I guess it will be easier to learn with them since they have such a huge transfer budget and get to play against better teams.
If you come across something you don't understand, ask, whether it's here or over there. We all started with zero or little knowledge at some point.
You had basic issues. Only one player consistently attacking the box. A very aggressive midfield, which may see you leaving big gaps defensively. A backline all on defend, which apart from being a little flat in defence, also provides no usefulness with the ball. The TIs were probably an attempt to fix the basic issues you had, but they were a mess, tbh. Start with fewer (or no) TIs and add them when you see you need them. THoG's guide describes TIs and PIs (among other things) brilliantly.
You need more than one player attacking the box regularly for a general working tactic. That's not to say other tactics cannot work, but they're more specialised.
Movement between the lines is important. I winger holding position or coming inside, leaves space (by drawing in his marker) for an overlapping fullback. A striker dropping deep or pulling wide, pulls defenders away from their position, ready for a midfielder (wide or central) to take advantage by attacking that space. A midfielder needs too screen the defence to cover for an attacking fullback. There are many more scenarios, but those will maybe help your thinking along.
As I said though, if you don't know or want to learn more, please ask.
EDIT: I'm very surprised you got away with that tactic. I'm hoping for an improved AI this time around so that tactics like that won't get so lucky and we don't dominate as easily.