1. git clone https://github.com/Misiur/openfl-custom.git
2. Edit files in assets/templates/project to fit your needs
3. cd openfl-custom
4. haxelib dev custom .
5. Navigate to parent folder of your new project
6. openfl create custom:project ProjectName

In case there will be a haxelib project named custom, use a different name

openfl create custom:User/Template ProjectName which will download a https://github.com/User/Template.git would be really nice, but that would require changes in lime core.