Unfortunately, Standard Assets 2018.4 | Check out Starter Assets: First Person & Third Person is no longer available.
This package has been deprecated from the Asset Store. This means that new purchases of the package are not allowed and that only users who already purchased or downloaded the package before it was deprecated, are allowed to download it.
Just wanted to let you guys know if you didn’t already.
It also looks like their Terrain pack from the previous section is now different from what you used, as the “dirt” option is no longer there.