Firstly if you decide to manage the club you support some times it is easy like if your a chelsea fan but others it is much harder like if you were a gretna fan as the financial state off that club is alot worse meaning if you sign big players with big contract demands then you will only be able to have a small sqaud.But if you check out the reccommended players page ounce it is constructed and there will be players who are likely to be as good as the players who want big wages but work for alot cheaper. This is either because they are quite young but will become future stars like Bojan a striker from the Barcelona B team.
Then it comes to tactics you decide these on what your sqaud is like if it has lots of attacking players you would set it to be very attacking and vice versa with defensive players. Tactics are also decided when you get your scout report on your next opponnents and you should change them to fit so you dont lose your next game.