In case where symbolic link is not allowed is described in the tutorial step 10.
The key element is to configure your hosting server correctly to provide the same directory path for the different domain and sub-domain like this is the case with Windows platform
In summary, you have to configure you hosting server to have for example:
www.master.com = /public_html/master_dir
www.slave1.com = /public_html/master_dir
www.slave1.com = /public_html/master_dir
Notice that all the domain are assigned with the same directory path (the master root directory)