we don't have a step by step tutorial for accomplishing this.
We cant provide you with a step by step tutorial, but we can offer assistance if you are having difficulty with a specific part of creating this.
I would start by going through the tutorial on the security assist and data assist pages to become familiar with how the tools work.
Use security assist to create the login portion.
Use Data Assist insert record to store the appointment details.
I would think the minimum you would need to store in the data base is the date, and time for the appointment and the logged in users ID.