TL when to create custom module?

I have arequirement to a add a list of favourite properties linked to the site members.
i.e a registered user with site can mark properties as favourite.

I've already created new table for favourite properties with FK as Userid and PropertyId.
I came acroos this tutorial to create a custom module
http://dev.typolight.org/wiki/1/TutorialsExtension
Do i follow these steps?
What will be the best way to do it and how?

I'd say make that Tutorial Custom Module first, then see what you still don't understand specifically

Well the problem is that your data model does not fit TL very well. I would start by looking at Tasks module - it provides custom rendering for individual tasks, maybe you can change it to fit your data model somehow.