What  may help you is some webearches on the subjects of:

#1    Ecumenism

#2    Ecumenical

1) I have found Wikipedia's articles to be good and reliable. If you want a quick source for the basics of a religion, it's a good place to find them.

2) I'm not sure what your question is or what your assignment is. I will mention one idea, but it is just an idea:

"Judaism, Christianity, and Islam: three branches of the same tree."

i just dont want to go deeper but superficial