Welcome messages were introduced in version 2.1.2 of UiPress and are very simple to add.
Navigate to the UiPress settings (main menu > settings > UiPress) and click on the overview tab. Once on the overview settings tab you will see an option called Custom welcome message.
Here you have a choice of just entering very simply text welcome messages or you can add HTML for more complicated ones.
Once you have added the the content you want for the welcome message, you can click preview to see how it will look. After you have everything the way you want, press save and navigate to the overview page and if you have followed all the steps correctly your new welcome message will be at the top of the screen!