IMMD

I have a multi room wired audio system throughout our home. In the room with all the components, there is a single input jack that I intend to plug into an echo dot when it is delivered. All my music is on iTunes and I need to know how to utilize the songs I have via the dot. I read somewhere that amazon music app can use iTunes songs. Also if my dot in the components room can't hear me in the living room, can I just get a second dot to interface with the first one? Thanks!