- how to link a menu-item to a newly created page, because I don’t know the url.
Go to "simple menu" type the name and select the page you want to link to from drop down menu
anywhere in the page you can link to /page-name-here (when you create new page you type the name you want to use)
- how to insert code into the page because I need much more then just some text.
if you need more you will have to create widgets or addons that will allow you to do that