Confusion leading to frustration

Hello all. I'm in a conundrum. I have not been to a real wedding since 2005. Even then I had very little to do with the planning bc I was stationed overseas. I have managed to miss all my cousin's wedding over the years due to military functions.....deployments, training etc. Our friends are mostly military (we are both active duty) so none of them did "real" weddings. Whole lot of court house marriages. I give this to lead into my lack of knowledge.
My mother has been an amazing help through this but she tells me some wedding etiquette and I will read things in here and it's a complete 180. Is there something that says what the current etiquette is for certain things? Gifts, guests, food, things like that. Maybe this is because my life revolves around instructions....
Thank you all in advance for any advice provided.