It not complicated, you have a referee, you have some notes about what your character is capable of. You describe what you want to do based on the circumstances. The referee then tells you what happens or what to roll if the result is uncertain. Rinse and repeat.
Either the referee knows the setting cold and is capable of consistent rulings in which case it likely the campaign will be fun and last a good long while.
Or the referee doesn't, in which case the campaign will fall apart and the group will try something else.
What make doing this a tabletop roleplaying campaign is a focus on each players playing a individual character and doing everything from the point of view of that character.
It not novice friendly and has a steep learning curve. It demands that the referee be an effective communicator, coach, consistent, and above all fair.
The advantage is the focus on the setting of the campaign, and worrying about what you can do as if you are there rather how to manipulate a set of mechanics.