How do Premier League teams downgrade?

Competition team * * *, a total of 20 teams, the competition adopts the double-cycle scoring system (double-cycle: the two teams play twice at home and away respectively. Scoring calculation: the winner of each game gets 3 points, the loser doesn't get any points, and the two teams each get 1 point in a draw. Finally, the ranking order is based on points. If the points are the same, the ranking will be distinguished by the difference between the number of goals and the total number of goals. In addition, the three teams at the bottom of the Super League rankings are relegated teams; From the Championship 3 team to the Super League competition; The first runner-up of the British Championship will be promoted directly to the Super League, and the other four teams ranked third to sixth will adopt the home and away two-round elimination system, third to sixth, fourth to fifth in the Championship promotion play-offs. After the draw, it will be decided which team will play at home first, and the last two winning teams will play a game at the neutral stadium before the winner can advance.