I would like to display or not some fields according to choices made in the choices fields, how could I do that?

For a choices field named "Choices" you add the following code to the "Display field only, if" property of the field that you want to show or hide based on what is selected from the choices field.

contains(text('Choices'), "Address")

In the above example, the Address field would become visible when the user selects "Address" from the Choices pop-up field. You are not limited to fields. You can show/hide other form elements like a view that shows a related table, etc.

Be aware that adding Tabs to a form is another way to hide/show form elements without the need to write any code. If you click the Tools icon on the left and select "Edit fields". Then at bottom of right panel click "Add layout element". Then drag Tabs to center panel. The order in which you place the tabs will determine which form elements are hidden or shown.