The criteria for the classification in the first phase of the Tercera División, which is part of the Spanish football league system, typically includes the standard league format criteria used in football leagues. These generally involve the following:

1. Points Per Game (PPG): Teams are ranked by total points, which are accumulated via wins and draws (3 points for a win, 1 point for a draw, 0 points for a loss).

2. Tiebreakers: In cases where teams are tied on points, tiebreakers are usually applied in a specific order, such as:

   • Goal difference.
   • Number of goals scored.
   • Head-to-head record, including away goals in head-to-head matches.
   • Possibly a play-off match if teams are tied in critical positions affecting promotion or relegation.

3. Group Performance: The league is divided into multiple groups based on geographic location, each comprising different teams. The performance in these groups determines which teams progress to playoffs for promotion.

These general principles apply to many league formats, but specific details might vary slightly. Unfortunately, exact classification criteria specifics for each phase are often detailed in official league documentation or press releases from the organizing body. For more detailed information, you might refer to official documents from the Spanish Football Federation or local sports news regarding the Tercera División.

For further insights, you can explore Wikipedia's article on the Tercera División for a broad overview.