Aluuvian gave a good explanation and you should understand the situation fairly, but no better could you then when you read the book your self -
bible.com is a
good start. All churches use the same bible and bases, but the all made changes, added this and that, chiefly the Roman Catholics, who added lines to the words spoken and changed lines etc. But the bible is by far the same with all the churches.
If you want to understand the churches and their differences you must first know/understnad human nature.
We each learn differently: visually, orally, practically, and all thos are employed in a course.
It is the same in christianity as God intended it this way. When he said to
Peter ‘upon this rock I shall build my church’ he meant to place peter as leader of the apostles, whom all formed his church - and they were all different churches:
evangelist Paul, Peter to the church and Mark to the orthodox church, preachers and ministers Thomas etc.
You must understand that thus is mankind and god knew
it and gave each an environment to worship him in. What he does like is the violations of the churches and the changes they made - the Roman Catholics namely
whom he refers to as ‘The whore that sits upon the seven mountains’ referring to the vatican which is build on seven mountains - see the revelation and the
nicholations ( Roman Cat.)
The christian churches therefore should not confuse you for thus God wants it; because as long as you bide by the bible, his teachings, you are in his favour. So,
really, you must read the bible first. Start with the new testament, if you wish, the story of the christians.
And…jesus actually did say that we need not join any church to worship god as god is a spirit and we should worship him in spirit and in truth. John 4:20-25