Hello Newquest78!

I will duplicate my answer to you in support:

Let's review your questions:

1) if i will create more then one custom function, How i call and use the core function of the UNA
--- first of all, you need to have the advanced PHP editor or environment tools like Netbeans or Zend. It will help you to operate with the complex projects like UNA. Especially with the showing of the functions / methods of the included files. For example, here https://github.com/unaio/una/wiki/Common-Mistakes you may see that you can call the function bx_file_get_contents instead of file_get_contents. So this is the common scheme to use to core functions of the UNA - firstly you need to "connect" the source core files with the bx_import('BxDol[Class name]'); function then use this class by the next plan:
BxDol[Class name]::getInstance()->[some method]
with the Netbeans, it will be visible more "noticeable". Also, check the following sections in our Wiki:
https://github.com/unaio/una/wiki/Code-Convention
https://github.com/unaio/una/wiki/Common-Mistakes
2) Also please let me know if i create a form in html on the page and what action i pass to it so that what ever user pass value in the form i can get that and use to insert in database.
For UNA this is better to create forms with the keeping all the points for manage fields etc according to this manual:
https://github.com/unaio/una/wiki/Dev-Forms

The structure of modules was described here:

https://github.com/unaio/una/wiki/Directories-structure#module-structure

Please review all mentioned links and specify what is left there unclear for you.

With the best regards, Leonid