Much of what happens during your pet's transition is up to you. You may elect to make it a very quiet, personal experience with just you and your pet. You may elect to have a "celebration of life" with friends and family who have been important in your pet's life present to share memories and stories. You can play music you find comforting. You can light candles. You may choose to be outside in your pet's favorite part of the yard(weather permitting) or inside, snuggled in their favorite bed.
When the doctor arrives, she will go over important papers first so that there is no need to worry about that after. Your pet will be given a sedative to help them feel very relaxed and comfortable. An IV catheter will be placed in most cases. When you are ready, the final injection will be given.