My sister is marrying a man of Jewish faith! What are some things I should know as a non-Jewish person?

I have unfortunately had very little exposure to Judaism in my lifetime but I want to be as supportive of my sister as possible. What are some cultural customs I should be familiar with? I tried to look it up but the history of the Jewish people is massive and my research hasn’t done much to help discern what is important to know for my first interactions with her new family at the wedding. Thank you!