Classic Want to try healing

Hey there, i recently hit 70 on a priest, I have always wanted to try out healing but I am afraid of healing dungeons , I am less afraid of healing raids and was wondering if u can play an alt that mainly only raids or if dungeons would be vital. And if they are! Whats the best way to learn m+ healing? Just some guides/heroic/low mythics or something else?Mainly want to learn holy priest if someone knows some video guides! via /r/wow https://ift.tt/qlXT9QM