Weekpicker doesn’t work

Hello Team,

I am very interested in buying your plugin because it is the only one that offers me a field, weekpicker.
I also need to add two other types of fields more classic (text field and datepicker).
So I tried the free version to test the weekpicker field.
Unfortunately it does not work at all and does not display selectable weeks.
Is there a particular serup to do for this field?
Thank you in advance to come back to me as soon as possible, because if this field works, I could buy this plugin without hesitation.

Thank you in advance for your explanations.

Philippe