Currently the templates are targeted at Hopper SDK 4.7.3+ providing some basic options.
cp -R *.xctemplate ~/Library/Developer/Xcode/Templates/Hopper
The templates should then be available in Xcode when creating new projects (File->New->Project…, in the "Hopper" category).
The Hopper SDK should be made available to the plugin by copying the include
SDK directory under a directory named 'HopperSDK' in your project source root. If you use Git in your project, you can achieve this by adding the SDK as a submodule to your source tree:
git submodule add -b include https://github.com/makigumo/HopperSDK-v4.git HopperSDK