You will need to set up two additional lists and provide the choices as list items, apart from this one list you are building the Cascading dropdown.
Here are some links with tutorials you can refer to for this requirement:
Cascading Dropdown in SharePoint List using Infopath Forms.
Video guidance: Cascading Dropdowns in InfoPath.
And the outcome would be:
If the response is helpful, please click "Accept Answer" and upvote it.