Need some help on POP-UP!!!

Hi Shaik, if you want to show any interface as a pop up then create actions to that particular record and attach an interface to that action.
And in case you just want a pop-up interface for confirmation purposes before completing an action or moving to another interface then use
"comfirmHeader" parameter available in a!buttonWidget() component.

I will post an article on my blog soon. It includes an example of how to show a pop-up window in Appian. This is not rocket science, you just have to hide your UI and show a card layout with shadows enabled instead.

Find the example below:

a!localVariables(
  local!showPopup: false,
  {
    a!sectionLayout(
      showWhen: not(local!showPopup),
      contents: {
        a!textField(
          label: "Text",
        ),
        a!paragraphField(
          label: "Paragraph",
        ),
        a!buttonArrayLayout(
          buttons: {
            a!buttonWidget(
              label: "Show Popup!",
              icon: "arrow-right",
              value: true,
              saveInto: local!showPopup,
              style: "PRIMARY"
            )
          },
          align: "CENTER"
        )
      },
    ),
    a!columnsLayout(
      showWhen: local!showPopup,
      columns: {
        a!columnLayout(),
        a!columnLayout(
          contents: {
            a!cardLayout(
              marginAbove: "EVEN_MORE",
              showBorder: false,
              showShadow: true,
              contents: {
                a!sectionLayout(
                  contents: {
                    a!richTextDisplayField(
                      labelPosition: "COLLAPSED",
                      value: {
                        a!richTextItem(
                          text: {
                            "This is a fake popup window!"
                          },
                          size: "MEDIUM_PLUS"
                        ),
                        char(10),
                        char(10),
                        "And shows some text to the user."
                      }
                    )
                  },
                  divider: "BELOW"
                ),
                a!buttonLayout(
                  primaryButtons: {
                    a!buttonWidget(
                      label: "OK",
                      icon: "check",
                      style: "PRIMARY",
                      value: false,
                      saveInto: local!showPopup
                    )
                  },
                  secondaryButtons: {
                    a!buttonWidget(
                      label: "Cancel",
                      icon: "times",
                      style: "NORMAL",
                      value: false,
                      saveInto: local!showPopup
                    )
                  }
                )
              },
            )
          }
        ),
        a!columnLayout()
      },
    )
  }
)

Hi Stefan, this is rocket science.  As we have asked to display the pop-up, not the "fake pop-up" screen. As the common understanding, pop up should look like this - 

Only option in that case is a Record Action that opens in a dialog.

LOL ... I know. But I do not know of any official definition of how a pop-up has to look like. And I think that it is more about the purpose in terms of UX, than the looks in terms of UI.

instead of a record type. A site is a custom web page that you can create in Appian to display interfaces, reports, or processes. You can use a site to display your read-only interface and add a link or button to open the record summary view in a new tab or window. This way, the user can easily go back to the site by closing the tab or window.

instead of a record type. A site is a custom web page that you can create in Appian to display interfaces, reports, or processes. You can use a site to display your read-only interface and add a link or button to open the record summary view in a new tab or window. This way, the user can easily go back to the site by closing the tab or window.

I got it