Finding relevant companies

I have been developing an application to find companies with a specific profile.
User can write (in natural language) which companies they looking for and application will return the list of companies fiting the criteria, with emails and/or phone numbers.

I am new to pipedrive and not sure how to best implement it as a plugin in the sandbox. What would be the best approach for it?

For the first time App developers, your can refer the tutorial below: