Just for the record, the current version is 1.9.12 (http://osTicket.com/download) and so before starting with an old 1.8.x version, you should go with the latest version instead ;)
Beside, please don't use xampp - a lot of people are having issues with it (sooner or later) and so I suggest to better use IIS or Apache.
Regardless of the things said above, could you tell for what exactly you'd like to have a step by step guide?