I will try to explain here because cannot add images in comments:
First you need to create an enumeration that you want to use (see documentation https://docs.mendix.com/refguide/enumerations) in my example below ENUM_Test
If you have created this enumeration you can set this enumeration as a data type from an attribute in your entity (Test) in the domain model
Then you need to go to the page where you want to have these radio buttons and these in a dataview of your entity.
Below you can see that we have radio buttons for attrubute Selected (data type boolean) and for Attribute (data type Enumeration). I hope this helps you a bit.
You can create radio buttons with 3 options if this is linked with an attribute of type enumeration.
Radio buttons are used for enumarations. If you want start an action then this can be an option. Retrieve the attribute in which you made with enum. For each enum case start a microflow simply.