Graduation Photos w Film Advice

Hello, I am about to graduate college and I am planning on taking some pictures for my friends and I with my Canon AE-1 film camera with Kodak Portra 400 film. We are planning on taking photos on an early morning and I was wondering if bringing my attachable flash would create a cool effect on the portrait even in the daylight. I am not too experienced with film, so I will be taking the photos with the program setting. Any advice?