When you say there is light, you mean there is a flash, right? Then set it to your shutter synchronization speed, which is generally1125 s. If there are other bright lighting devices in the room at this time, then we can reduce the speed appropriately and introduce some live light to make the film light less hard. But the minimum must not be lower than 1/30S, otherwise there will be phantom. In addition, flash compensation should not be touched, and exposure compensation can be increased by 2/3 (because weddings are usually high-profile photos, mainly white). Also, ISO had better be automatic.

When you say there are lights, if you only mean indoor lighting, it will be more difficult. This will test the sensitivity of your device. Generally speaking, because you use more snapshots, the speed can't be lower than 1/60S. In this case, I am afraid that the ordinary SLR ISO will reach more than 800. At this time, the noise is highlighted.