what will the su password inside the kosmtik image using docker on windows

[toqeer786]

i had installed kosmtik using docker from this : https://ircama.github.io/osm-carto-tutorials/docker-kosmtik/#docker-toolbox-for-windows,, i want to export tiles through kosmtik tiles-export-plugins when i run the command it gives permisson denied error here one thing more when i enter su using docker command it ask for the password so what will be the su password ,any one have an idea about this ?????
here is my command and logs please check it :
first of all : docker exec -it e9a8c9e56a2d bash
it enters into container: I have no name!@e9a8c9e56a2d:/openstreetmap-carto$ su
Password:
i dont know the password and neither i had set the password at the time of docker pull ,what will be the password for su ??