The music you choose must be appropriate for a service of Christian worship. If you have in mind some popular songs that have been meaningful to you during your courtship, it might be appropriate to play those during your reception, but not during the ceremony itself. All music for the service should be approved by the officiating pastor. Music can be added during as many of the four sections of the service as desired, and certainly should be there at the beginning and the end. This is the context within which a Christian wedding celebrates your love for one another, and recognizing that is a fitting to begin the ceremony.
Some people find a unity candle to be a meaningful symbol.
If you choose to include it in your wedding, it should be after the second vow is spoken. That spoken promise makes the difference. A new relationship is initiated. And that vow forms the foundation of the relationship to be built upon it hereafter. No, not even love.