I am using the latest version of Unity but when I click on Assets and then Import Package, there are no assets, please help.
"Import Package..." is for installing a Unity package file that you downloaded from a third party (such as a Github release or something). What you probably actually want is to navigate to Window -> Asset Store and find assets there that you want to download and import.
This is completely normal. Using the "Assets -> Import Package..." menu is only for packages you've downloaded manually through a browser, obtained from someone else, or have created yourself by exporting the assets from another project. For assets you've purchased from the Asset Store or have received as part of a bundle when subscribing to Unity, you need to import it from the "My Assets" section of the Asset Store which you can reach by clicking "Window -> Asset Store" and then clicking the "My Assets" button. Check the image below for the location of the button.