Search, select and get info in a form

Hi,

I'm trying to create a form, where I can search for a user, select that user, get user information, edit the information and save it.

In more details: 
I have a User-list and a Form-list.
The Form-list have a form associated called EditUser. This form is activated by pressing an icon/link in SharePoint and this opens up the actual form. The EditUser form has a query field, result field and some user information fields. Look at this sample form:

The workflow is as follows:

1. Type in a search query and press search. (Optionally, the search happens automatically, as the query is typed in.)
2. Select a result from the results list. This will load the user information from the user list into the First name and Last name fields.
3. Now the First name and Last name can be edited and saved.
4. A new item is now created in the Forms-list, where a workflow will do some stuff before saving it to the user-list.

My challenges are the following:

1. Creating a result box, that is populated with filtered results when pressing Search.
2. Loading information, when selecting a user from the result box.

I'm a novice in the world of Nintex Forms, so some guidance and/or hints would be very much appreciated.