Hi Annie. I am a believer in the triune God. This is not some three-headed God. It is the idea of three distinct persons in one God. God the Father, God the Son, God the Holy Spirit are one yet three. Every once in a while I think I fathom it and then realize I can't. I am no scholar but this is how I reconcile it
1.In #1 you asked, how does it all all up. The simplest way I can say is 1x1x1=1.
2.God is love, right? Can one single person love effectively amongst himself alone? I say, NO. You need at least 2 to love. Therefore God must be more than one and always has been. Yet God is One. Three in one to be exact.
3.There is God the Father, God the Son and God the Holy Spirit, one yet distinct. God the Son prayed to God the Father when He was on Earth.
4. This question is very interesting. Triune believers hold that God Himself was crucified, God the Son, who commended himself to God the Father. Thats part of what makes it so amazing, and makes it make sense also. Gods life for us because He loves us.
Scriptures support both the Diety of Jesus Christ and the Diety and personage of the Holy Spirit.
Hope this helps....