Paste the .xml file inside templates directory inside your PhpStorm Config Directory
Usually Config directory is found as under:
Syntax
%HOMEPATH%\.<product><version>\config
Example
C:\Users\JohnS\.PhpStorm2018.3\config
Syntax
~/Library/Preferences/<product><version>
Example
~/Library/Preferences/PhpStorm2018.3
Syntax
~/.<product><version>/config
Example
~/.PhpStorm2018.3/config