@Margo I am not sure how to do this. SharePoint online does not have a cascading dropdown field and the images in the document you sent me do not match what I currently see in PlumSail Forms.
After reading your post I did more research on how to create a look up field.
For me to be able to use a look up field. For me to get it to do what I want it to do I need a choice field and choice fields are not supported when trying to create look up fields. There is an image below directly from Microsoft that states what is supported and what is not.
That is correct, you can't select the choice field as the source for the lookup field.
You can store companies and user roles in single-line text fields, in separate SharePoint lists, and set up its dependence. Thus, that will be easier to administer data and easier to create cascading dropdowns.
Another option is to populate common dropdowns with options dynamically, and then pass selected values to the SharePoint field. Please see the example here. Note, that this option is less universal and stable.