When you want your customer to select from multiple options you can use the Text Menu component.
For creating a menu you open the flow builder:
Add the Text Menu flow component
In the message you add the options as a numeric menu, like with options to simplify the selection to the user.
There is a default option "Unexpected reply" that is triggered when the customer enters a number or text not in the avaliable options. This option can be connected to any other component or ti the same Text Menu component.
Every reply option added can be connected to other flow components.