After you select "Import from YML of Yandex.Market" in the menu that appears, insert a link to your directory in this format and click "Import".
In the case of a successful synchronization, you will see an alert:
In case of unsuccessful synchronization, you can check your directory correctly.
This can be done at a special service from the company Yandex:
The service, select "Store", please indicate the source "by reference", insert the address of the directory in the proposed field and click the "Check".
In the case of successful verification, you will see an alert.