1) I have no idea what you saw on Youtube, nor do i care, so please do not post a link. The spell sounds like a typical hoodoo bottle spell, but see my reply to (3) because there is some question in my mind about why you did this spell, whether you put both parties' names in it, and what your intentions are.
2) "We" (by which i mean "don't include me!") do not know any such thing as that "every spell has side effects." I have no idea who taught you this, nor do i care to affirm or deny your personal belief. I think you should speak to your own Youtube instructor about this belief, because you are asking me to evaluate something i do not even believe to be true! However, if for some reason, participating in this forum is of interest to you, then , regarding beliefs and opinions about spell "side effects," please see this forum thread and discuss that matter there, not here:
Can Spells Back-Fire, Blow Back, Reverse On Me, or Harm Me?can-spells-back-fire,-blow-back,-reverse-on-me,-or-harm-me--t40.html
3) I cannot evaluate adding "more enemy's name(s)" to this spell. I think you may be confused about this spell. Did you start your bottle with the names of both parties to a marriage or a long-term affair? Then that is your spell. No other people would be involved. If the person is a player and has MANY casual lovers, then a bottle spell for the break up of an affair or marriage is NOT what you want and since breaking up an affair or marriage is the topic of this thread (see the title of the thread), then you may be asking the question in the wrong area of the board.
4) You would wish to deploy the spell where the married couple or couple engaged in a long-term affair (to which you are the outside party) would have to walk over it. See these web pages for instructions: