visit the Amazon rainforest

I’ll be in Peru and Chile starting in February and wanted to visit the Amazon. Time isn’t really a big factor and my friend and I speak English and Spanish. We want to do the trip relatively inexpensively, but with a guide and including a lot of hiking/backpacking. Any advice on such things as which city to start in (Manuas, I’m guessing), how to find a good guide, what to see, which parks to visit, would all be very much appreciated.