GC Testimonials Form help

I have installed GC Testimonials, and added short code to add Testimonial form on my reviews page. I need only a few fields such as; Name, Email, Subject, and comment. How can I edit to remove fields such as company name etc that are installed by default. I tried to remove fields in one of the files, but then the form looked staggered on the page and not a clean square block. Any Suggestions would be great. I am kind of new to word press so sorry if this is hard to understand.