[Alternative112]

Positioning the dialog box to the right of the screen might be very hard or impossible to do (let me know if you pull it off). As for the dialog, you will want to use DIALOG_STYLE_LIST in SendPlayerDialog(). then in OnDialogResponse, the variable listitem in that callback will contain the list entry that the player entered (STARTING AT 0).

Try it yourself before asking for an entire script, you will learn more that way