Deprecated: The each() function is deprecated. C:\xampp\apps\magento\htdocs\vendor\colinmollenhour\cache-backend-file\File.php on line 81

This is probably because you use php 7.2 which Magento doesn’t support currently, even in 2.3 pre-release. You can downgrade to php 7.1.X and use Magento 2.2.X or downgrade to php 7.0.7.X and use Magento 2.1.X.