That opens a dialog box where you can enter the full path to the shared folder, using the same \\Computername\Sharename syntax. If you start from the Network folder, browse to the shared computer, right-click a shared folder, and then click Map Network Drive from the shortcut menu.
You can choose either of two techniques to create one of these network shortcuts, which I've numbered in the accompanying screenshot:
The time-saving, frustration-free alternative is to create mapped shortcuts to those shared locations so that they're always available when you click This PC in the File Explorer navigation pane. It can also be frustrating if an available network resource isn't visible in File Explorer's Network node. Browsing for shared network resources can be a tedious process.