Would appreciate some expert advice for sex for the first time?

Make it wonderful: Be sure it's someone you really like. Bring barrier protection and spermicide or other reliable birth control. Take it very, very slow. Hold one another, undress in stages. Try lots of different things short of penetration. Give serious thought to bring one another to climax short of intercourse. Be ready to use your entire body. Communicate what you find you like best. Whatever happens, cherish.