There are some parts in instances where I get confused, but typically I pull up the wiki once I get into a relatively safe spot. For example I was confused with the orbs in the last quest of season 4 episode 1 and I figured it out on the wiki and completed it just fine, and I'm in exotics and working on ascended, and I'm still kind of unfamiliar with the game (I'm used to MMOs like WoW and FFXIV).
The wiki is your friend, it has info on all the instances.