Please can come one explain to me what this means ?

Hello,

The "Clubs" column lists the number of clubs whose managers have visited the country.
The "Pot. for potential and (8) it's the level of the youth academy" column lists the potential found by managers who have a youth academy at the same level as yours.

Leguman: Bonjour,

La colonne "Clubs" liste le nombre de clubs dont les managers ont visité le pays.
La colonne "Pot. for potential and (8) it's the level of the youth academy" liste les potentiels trouvés par les managers qui possèdent un centre de formation (youth academy) de même niveau que le tien.

Is there any way to figure out the potential in the countries that are blank?

Hello,

No, not to my knowledge ...
But on an old subject, the webmaster mentioned that the probability of finding a "big" potential was the same, whatever the country.