Connect existing Shares in Owncloud

Hello Communit

I did Setup the owncloud plugin and I am able to Access the "Default" share in my local Network.
However I do not understand how I can link my already existing cifs Shares that I use for backup into owncloud. I saw that in the plugin there is a tab "Shares" and I thought that when I enter the Shares and then save the config log out and in into owncloud I will see them but this is not the case. Do I Need to move the whole Share structure underneath the owncloud Directory or is there a way to map the Shares into owncloud. Will a Linux symbolic link do the trick?
And my other question is what I Need to put into the config.php for the trusted Domain Setting so that I can Access the owncloud from public Internet. Does this Need to be my external dyndns Name ?
Thanks for a short help

Hello Thanks for the Feedback. I an using the original i guess owncloud 6 plugin. In the omv webgui There Are only a few settings but nothing with external storage. However there is a possibilty to add local omv shares but the Do Not appear.