Once you have successfully connected to a machine, the spinning orange icon changes to a computer. Tap this again to show the list of shares. If you don't see any, check for the following problems.
You might not have shared a folder yet. There are instructions on how to do this at the link below.
Admin Shares usually have a name with a $ at the end, but FileBrowser will show these as drive letters, such as C:, D: etc. You may need to enable Admin Share viewing in FileBrowser. Bring up FileBrowser's Config Page to see the 'Show Admin Shares' switch in the 'File Browsing Preferences' section. More information about Admin shares is available from the link below.
The computer or network storage device you connected to may not allow you to see all the available shares. In this case you need to add a share name to the list manually: