Well, using them would be the main thing you did wrong. Basically because you don't know what you're doing or what they mean, and also because tactics aren't universal, ie not all players will fit into all tactics.
If you rarely watch football matches, you can't be too interested in it, which makes me wonder why you would play a game like FM. I would suppose a game like FIFA would be more up your alley, and that's not in any way meant as an insult. FIFA is more skill-based when it comes to hand-eye coordination, something you don't really need to be a football guru to master. It's also more action-based and fast-paced, which I would think would suit you better? FM is more about understanding the depths of the game, and all the stuff that surrounds it. I have friends who "rarely watch football matches", and there's no way in **** they would ever be interested in a game like FM.
EDIT: Just to avoid any misunderstanding, I'm NOT trying to tell you what to play. I'm just trying to point out that you'd enjoy it a lot more if you took the time to learn it.