Be a Pro mode is a FIFA 08 game mode in which you control one single player on the pitch. Your ultimate goal is obviously to win games, but you should also be mindful of the rating bar near the bottom of the screen which determines how well you have played. Your game ratings do not necessarily reflect how beneficial you were to your team, but just how well you did according to the game's standards, so don't get discouraged if your ratings are consistently low, as you still may be a key part of your team regardless of what the rating says.
You have the option of playing an offline game in which you control a single player in a game with every other player being played by the CPU, or playing an online match in which most players are controlled by other players. Right now, we are just going to focus on the offline side of play.
To start an offline match, go to Main Menu - Game Modes - Be a Pro: Offline Training. Once you do this, you will see a legend which lists how you can improve or damage your game rating. A copy of this legend can be seen below.
The positional indicator tells you where you need to be on the pitch. Using the arrows as a guide, follow them until they disappear, meaning that you have reached where you need to be. They will have one, two, or three arrows, three meaning that you are far away or that it is most urgent that you get to this position.
The offside indicator will appear if you are offside. If you ever see this little flag, make sure you get onside immediately to avoid loosing valuable experience points, or risk wasting an attack on goal by being caught offside.
The threat indicator lets you know which players of the opposition are dangerous, you should mark these players and try to ensure that they don't get the ball. This occurs most when an opposing player is about to take a free kick.
Once you've got a good idea of how the rating system works, advance to the team selection screen. Once you've picked your team, you can choose which player from your selected team you would like to play as. Advance through the next page, selecting your preferred settings and you're ready to go.
Taking your Be a Pro skills online is both fun and challenging. Once you start an online game, you will realize how different online play is from the offline game mode. Although the general concepts are the same, the fact that your team is made up of all individual, real players and not CPUs makes it a lot harder. You may want to consider getting a team of players and play regularly with them to establish familiarity with the players. At the time of writing this, I would imagine that FIFA 08 Be a Pro online is pretty much abandoned. Newer versions of FIFA all feature Be a Pro, with even more features and the benefit of a lively online community, so you should look into buying a newer version of FIFA if you really enjoy Be a Pro.