Jeez, you are a complete newbie!
Anyway.
1.) Improve your ratings by consistently performing well in matches you play in(score goals,provide assists,try to complete your passes,try to dribble past opossition,keep good positions on the pitch etc you will learn while playing).
2.)Assist:- means when you pass to a player and he scores a goal,that is an assist. Try to provide many assists.
3.)Own goal is when you put the ball in your own goal by mistake(hopefully).
4.) When your dribbling rating increases a red triangle pointing upwards appears beside it to show that particular skill has increased. Same for all other skills like passing etc etc that you see there.
5.)Tenacity:- Dude seriously?? Tenacity - Definition and More from the Free Merriam-Webster Dictionary
6.) Improve defence skill by tackling players correctly(careful with the slide tackles or you will get red or yellow cards), holding up players running with the ball,making interceptions and getting in good positions when the opponent is attacking.
7.) You increase experience points by playing more games.
8.) C,A,B?? Game plans? They are alternate gameplans. suppose plan A is attack and plan B is defend. during a match if you are losing you can choose plan A and your team will attack more. Or suppose you are leading 2-0, you can choose plan B and your team will be more defensive.
You have to assign what gameplay style you want in the different plans like A,B,C.
Becoming a legend mode needs some patience since your teammates are being controlled by the COM and if you don't call for the ball they don't tend to pass to you too much in the beginning. SO get in good positions and call for the ball.
