I've celebrated so many weddings in the last couple of years where the couple has not engaged or designated someone to manage the actual events of the wedding day for them. It breaks my heart to see the couple take on that role and see them running here and there just before the ceremony begins. I find myself taking on the leadership of what I can for events leading up to the event itself. But, my main focus is to deliver the ceremony and ensure that all goes well.
If you've not had a wedding before, you will be amazed at the sheer volume of questions that need attention...right now!! Without help, usually the arrival of your vendors are not planned in sequence and you will find that some will be bumping into each other when getting their jobs done or spending time trying to find someone to ask questions. If you have not chosen a wedding planner (and for large weddings, they provide great value), you should really consider someone to manage all the events and arrivals that take place on the actual day. As a couple, your major responsibilities should be to arrive, get dressed, breathe, and be ready for the ceremony. You should not be consumed with figuring out when to take photos, when to cue the DJ, check to see if the food is ready, or whether the cake has arrived and been assembled.
My recommendation is to engage someone, even an organized friend or hire an event day coordinator to manage all the last minute details and questions that come up. If you have a large attendance of people (100+ guests) and vendors such as event staff, photographer, videographer, caterers, DJ, florists, wedding officiant, bartenders, etc., it will be worth the money to hire someone to answer questions and direct people to where they need to be, find power strips, whatever, so that you don't have to do it!
Once you do that, let all your vendors know who the person is, how to identify them on the day of the wedding, and let them manage the day from beginning to end. They should be the first to arrive at the venue and probably the last to leave. They are worth their weight in gold. Give yourselves a wedding gift and have an event day coordinator. They will contribute to a stress-free event and all you'll need to worry about is where you put your vows!