You can define a process that will display a form to the user and then display a "Thank you message" and OK button like this:
ENTER NEW MyObject
DISPLAY MESSAGE 'Thank you'
You can then tick the "Run Initialisation process" checkbox in the visual perspective and select the process you defined. This will make sure that the process runs when the user logs into the system.
However, currently there is no way to logout or reditect to another web page automatically from a process.