It greatly varies, depending on which one you join...although the rules are roughly the same, it's the price of players, and the marks given to them that is the big swing. The Sun (which I have never done) version gave man of the match to John Arne Riise on Tuesday, and thus he got extra points (????) which doesn't happen in the Telegraph version (which I do play...sort of. The gym I go to entered as a subdivision, running on the Telegraph rules, except we get NO substitutions all season...so if a player goes abroad or to a lower league, or is long term injured, tough!
The rules are usually in the papers, or web site pre season, along with the prices of players.
You usually get a budget of circa £50m with which to pick your team, and points are awarded/deducted (depending again on which league you join) for appearences, goals scored, bookings, clean sheets/goals conceeded, assists, etc.
If it's free, I might give the C4 one a punt, but it seems that most of them you have to pay for...

The past is history...The future a mystery.
This moment is a gift...That's why it's the present.