Multistore management is an option available from PrestaShop 1.5.x.
To enable the option, you need to navigate into PrestaShop backoffice > Preferences > General > Enable Multistore
Once the option is enabled, you can access the multistore management under Advanced Parameters > Multistore/Multishop
Then in Store Commander, you will have all the multistore options in the interface: the store tree, and various panels in the Properties column