Hi mirekg,
Thank you for reporting this issue. We have made a fix that will make the "Functions" and "Widget Gallery" menus available in the next version of Knowage.
"Models Manager" and "Resource Manager" are similar. The first one is for Community Edition and allows you to manage only the models folder to define metadata for data mining analysis. The second one is only for the Enterprise edition and allows you to manage all Knowage installation resources.
As for the home page, Knowage assumes that the first non-empty first-level menu is the one you want to use with the homepage. If you want to remove that document from the homepage, you need to make sure that all first-level menus are empty. After that, you can create a new empty first-level menu, a child menu of it, and configure the latter to run that document.
Greetings,
Alberto