Hi Nada,
You can use enitity level validation to give mulitiple validation on single attribute or you can configure it in microflow to check its empty and equal.
Refer this images below
There are several ways to do this. You could:
For the first two options, your validation flow will look something like this, with a validation per split:
Validation is also covered in the Crash Course:
https://academy.mendix.com/link/module/324/lecture/2934/7.4.2-Adding-Validation-Rules
So you can explore it at your own pace
I don’t know((