Well you can start with the main OOTB Change process and work from there, but in my experience, the change processes that have been developed by customers are many and varied and mostly are designed on the back of the existing processs within their business.
There will be many on the community who will have their own opinion of what constitutes a good ITIL change process, but in my opinion, there are a few key stages that you need.
How's that for a start point?
There is no way of importing the visio, however there should be best practices on the web. Failing that ServiceDesk does come with a Change process. I'm in the middle of trying to work out the best way of implementing standard changes.. query, category, template... so many ways....!