You don't need to pretend you understand what a false nine is. Here’s how to naturally ask questions so you can follow the game without annoying the die-hard fans in the room.
"Okay, I'm going to need the beginner's version of this: why was that just called a foul?"
"I know 'offside' is the hardest rule to explain, but can you give me the 10-second summary of what just happened?"
"Are we playing more defensively right now to protect the lead, or are we still trying to score?"
"So how exactly does the ref decide how many minutes to add at the end?"
"What’s the backstory with this guy? Is he our best player, or just the most dramatic?"
Ask during a break in play: a substitution, an injury stoppage, or when the ball goes out of bounds. Never ask a complex question when a team is actively attacking the goal.
Most fans actually love explaining their sport to newcomers, as long as you seem genuinely interested and you pick good moments (not during high-tension plays).