The specific first-class, second-class and third-class you asked are all divisions of league level. In the leagues of European countries, there is also a higher level than Grade A: Super League. This is only used in some countries.
The following is an encyclopedia link to the introduction of the five best leagues in Europe. You can have a look:
English Football Premier League. Uefa.com/football Europe /index.html
Website. Uefa.com/competitions/UCL/index.html has specific information about the competition system.
uefa europa league
The participating teams are the best teams in national leagues except the European Champions League, which is second only to the European Champions League in importance.
I'll show you the specific competition system:
. uefa . com/competitions/uefacup/index . html
3. In all countries, besides leagues, there are usually cups. This is another kind of competition different from the league system, similar to the difference between the Super League, the First Division and the FA Cup. Generally, teams at all levels can participate. It's not as important as the league. Some countries have two important cups, and the competition system of each national cup is different. Because of its low importance and attention, I won't introduce it in detail. I'll give you the cup links of the five major leagues. You can have a look:
England:
FA Cup: /view/7909 1.htm? fr=ala0
League Cup: /view/360866.htm
King's Cup of Spain: /view/2409943.htm
Italy Cup: /view/ 13089 1.htm
German Football Association Cup: /view/ 130936.htm
France: (Baidu has no link, Wikipedia will be censored)
FA Cup.
League Cup
Each competition has its own cup competition system. The general league is a double-cycle system, which spans the whole season. For the cup, some cups, such as the European Championship and the Champions League, have round robin first, and then knockout; There are also cases where other cups are knockout rounds.
Suitable for round robin, double round robin, single round robin, group competition, etc. There are points, not only points, but also other factors such as the team's record, goal difference and number of goals when judging the team's ranking. For the integral system, simply speaking, the winner gets 3 points, the draw gets 1 point, and the loser gets no points. For the knockout, it is to see who scores more goals on both sides and who advances; If there are as many goals at the end of the game, it is usually a penalty decision, and there are also cases of overtime.
Wikipedia also has information, but because it is censored, it can't send links here. You can search for keywords yourself, and you can ask me if you are not clear.