I ask to ask permission to cross to the USA, in cbx and where to ask for permission?

Are you going to San Diego airport? You should have your permission already done.

Hello, if you use the CBX from Mexico to Otay right inside the CBX in the middle there is a checkpoint, who has permission is still right, who does not go to the right to ask for permission as in any other checkpoint, first you pay the permit fee and Then they interview you.

If there is same they tell you where after they check your visa ...