The bottom line is that cloning an existing feature requires fully understanding the existing code for that feature which requires significant experience as a .NET developer. The article Cloning an Existing Feature is aimed at an audience that already has the required experience and that can read and fully understand the existing feature code. The main reason I wrote that article is to convey to people that they should not modify or fork the mojoPortal code as that will make it impossible for them to upgrade without losing their changes.
A contact form is something relatively easy to develop from scratch for most experienced developers, one could borrow just parts of the code (like the snippet that sends email) from the contact form or clone it fully but we simply don't have the capacity to help people step by step with custom development beyond the tutorials and documentation we provide, and our tutorials and documentation are generally sufficent for someone with the requisite background. For a qualified developer the source code is the best and most complete documentation available and we've shared it, but trying to help those who do not have the required background is just too much work and too time consuming to do for free.