So for context I'm a sorc main. During my time with ESO I also tried out other MMO's like WoW, GW2, BDO, as well as more recently FFXIV. All these MMO's had abilities for the pet classes in order to put away there pet, choose what target they attack, choose where they go, ect.
Now I was trying to find a way to keybind my sprint and auto run on a macro or on a easier key than the num key. But I found something interesting. On Y it said "command pet" I tried hitting Y out of combat, in-combat, looking at a target, nothing. So I googled it and found out it's Y+left click to have your pets attack a enemy and Y+right click to call them back. This is extremely useful for when your clearing ads and want your pets to DPS the boss or vice versa. It seems like it only works for the scamp or mabye it's just the most noticeable since the twillight is ranged. I think if people are playing a pet class this should be in the tutorial for them.
ex: Oh, by the way I should ask if you practice conjuration.
PC options: Why does that matter right now?
yeah I have a bit, why?
NPC response: Oh, well because when you have a conjuration out, you can actually order them around!
Then the tutorial explains that you can tell your pets what target to attack. I don't know if this works with necromancer but would be neat if it did.
TL;DR: The tutorial should tell you how to control your pets.