When planning a ceremony, many people do not know the specifics of how the ceremony should be conducted. Although I will go over the basic in this post, keep in mind that the priest, minister, bishop, or other officiant can help you in knowing the specifics.  Also, if you are having your ceremony at a event center, the manager/event planner can also advise you!
Another helpful hint is to do a rehearsal before your wedding day. It never hurts to do a practice run through to be prepared. Also, when using any children in the ceremony, it is important for them to practice and understand the procedure because unfortunately children are unpredictable.
The Groom- it is customary for the groom to enter first and be at the front by the officiator before the wedding march begins. When looking at the officiator, the groom should be on the right side.
Groomsmen- typically the groomsmen meet up with the bridesmaids at the rear portion of the aisle or they can also already be up in the front by the groom.
Bridesmaids- typically walk down the aisle with the groomsmen.  If there is a stair entrance to the ceremony isle, many will have the down the stairs before the bride. Others prefer to only have the bride walk down the stairs to create a grand entrance.
Others- the flower girl and ring bearer follow the bridesmaids.
The Bride- The bride ALWAYS comes last, typically being escorted by her father. At the front where the officiator and the wedding party stands, the bride is “given” to the groom from her father. She then hands her bouquet to the maid of honor.
During the Ceremony– the couple should stand facing each other, some do so while holding hands. The vows will be said when the officiator directs them to do so. The officiator will also lead the bride and groom to exchange rings at the appropriate time.

After the ceremony ends, many groups will take this time for the bride and groom to walk down the aisle to a specified location when the guests can congratulate the bride and groom.