1. Right-mouse-click on your select folder in the folders list and select Properties...
Fig 1. Location of Properties option
2. Go to the Permissions tab and click on Add…
Fig 2. Permissions tab
3. Type the user's name in the search field to search for them and click on the Add -> button at the bottom to add the user. Click OK to confirm selection.
Fig 3. Add Users box
4. The user should now be added to the permission group of this folder. You can also customise the level of access for this user by changing the permission options in the Permissions section below. Click OK when you are happy with your settings.
Fig 4. Example of customising the Permissions access levels
5. You have now successfully given access permissions to a user. The shared folder will also have a hand on the folder logo to indicate there is shared permissions on this folder.