MyFirstModule is already created for you when creating a new project to give you a quick start in building your project. This remains after you have downloaded the "ready to use" module Pizza Case in your new project. Of course when you only use the module Pizza Case you can remove it.
The Pizza Case is written in "English, United States".
Translations can be done manually by going to the properties of the Search button (Go to form Customer Overview, press on button Search) and fill in your case something in the property Caption. It is new in version 2.5 that the Caption of the Seach button is required.
Another option for translations batch translate (Edit Batch translate) and select "English, United States" and your project language. When "English, United States" is not listed go to Project -> Settings and add "EnUS" to the languages. After you have translated everything to your project language you can remove the "EnUS" again.
Translations and everything else is only visible in the front-end after deployment.
If you imported the module into a new project, you need other language settings, it should be UK.
In the on-line documentation there is a video which shows 'internationalisation'. This doesn't appear in my workspace. However if I click Project 'Project'/Settings, it shows the default language as en_GB. Pressing run leads us back to the same 16 errors.
I tried entering some text against the Customer.LastName when 'adding a new validation rule' but this doesn't make any difference and when I go back to the dialogue again the text has disappeared.
I can't incidentally see how to edit an existing validation rule. Althought there is a green blob against the field, the properties box doesn't refer to existing validation rules.
The only thing I am slightly suspicious about is my explorer shows Project, System, Administration, MyFirstModule and Pizza1 (my name for the download). I wonder what MyFirst Module is there for. It is empty.