Weinlick liked the idea, so he advertised for a bride on the Internet on a Bridal Nomination Committee Web site.
He devised an application form and asked friends and relatives to interview the candidates and select the winner. They did this at a "bridal candidate mixer" before the ceremony on the day of the wedding.
What is the meaning of the underlined parts?
In your story, the "bridal candidates" are the women that Weinlick has chosen to be the "finalists" in his (rather odd) competition to find a wife.
So this event is an opportunity for the female finalists to mix with his friends and relatives, and for those friends and relatives to give him their opinion on which one he should marry.
A very strange concept, if you ask me!