Creating a wedding day timeline is a very useful tool for both you, the venue and your vendors. It helps you clarify how the day will unfold but also allows the vendors to see how the service they provide will fit into the day. This is especially useful for your photographer and videographer as it gives them rough times as to when the key events of your day are going to take place. This allows them to plan in advance and work out best camera angles etc. Your venue and caterer will probably also ask you for a rough timeline of your day as they need this for planning food, bars and staffing.
This spreadsheet gives you a basic template to follow which includes all the key information that you need to keep your day organised. Fill this in once you have the information you need and you will find yourself feeling a lot more relaxed. Send the completed spreadsheet over to all relevant vendors and your venue. They will probably be very grateful.
You should also send(or print) this for anybody who is delegated a task on the timeline so that everybody has a clear idea of where they need to be.