You said templates right??
Easy peasy lemon squeezy hehe
Go to the templates folder, and copy either default or portal (the one you wanna use)
Once done, name it to anything such as 'new' 'beta' 'test'
Once renamed you can edit anything in the folder template wise and to see it, simply do this
To go back to your usual change the systpl=default whatever
Pretty easy, we wanted multiple sites and this worked for us, and helps on creating new templates.