Fire stick bugs

Fire stick bugs

I am very new to this whole streaming thing I feel I could pick it up fairly easily if there was a good source of knowledge. Thank you for that. My question is is this a reliable source or the bugs just part of the experience? Is there a way to store movies or cash them? Is there a better delivery system than fire stick? I notice I cannot do anything but stream over Wi-Fi is there a device out there that I can plug directly into my router?