Approval workflow

I am creating an approval app, in which I have created a request form with various fields. I have another table that has the approval details.

For example, in a request, the user selects a company, and the approval goes to the designated approver (which is specified in the approval details table).

company       approval 1                approval 2 

xyz               yyy@gmail.com         fhfhf@gmail.com

When the user selects "XYZ" in the request form and submits the request, the form should automatically look up the company associated with "XYZ". The corresponding approval authority for that company should then receive a notification to approve the request. Please note that I have already created "approve" and "reject" buttons, and I know how to send email notifications.