Dead by Daylight

Fugs guide has good information.

I will add that Legion is probably the best killer to get this achievement with despite it coming out with the Oni.

Legion is quick and with their power they can quickly track down uninjured survivors. Not only that pallets and windows don't slow you down towards injuring people.

Get everyone bloody and down the last guy. You can down more then one person but do not hook one until they get the other guy back up. Its actually a pretty good delay tactic if you have the opportunity.

As Fug stated, achievement doesn't count if other people are hooked or downed at the time of the hooking. Only injured guys count. I believe if they are mending this will still count as only injured.

Sloppy Butcher, Bloodhound, Franklins Demise, and Mad Grit are good perk choices but its up to you.

Add ons that add detection range and power extension are best.

Good Luck

This one is going to require some setup to make it easier and a lot of patience with getting survivors to do what you need them to do. I used the perks Infectious Fright, Coulrophobia, Thanatophobia, and A Nurse's calling but I highly recommend sloppy butcher if you can get it in place of infectious fright. The aim is to make healing take so long that they don't want to waste time doing it.

The first step in a match is to chase and down someone. If you find another person near the first victim, give chase and try to smack them. For me this frequently led to a chain reaction of the survivors sandbagging each other and leading me to the healthy ones or the healthy ones trying to help the current target.

Once you've managed to smack everyone, if the first person is down still ho hook them, but if they've been picked up, down your current target and try to get them to a hook quickly. (the perks give you some mercy time with heals taking forever but it's really best to try your best to get them downed and on a hook quickly)

Once in the scenario where 3 are injured and one is hooked, now we can chain these for the achievement progress. Lightly camp the hooked survivor until you see another. Almost always they will come. Immediately give chase and down them as fast as you can. While this is happening or as you're picking up the hooked person should get rescued, allowing you to add to your achievement progress. Rinse and repeat as possible.

Important thing to note, the survivors must be in the injured state. If any of the ones not getting hooked are down, hooked, or healthy you will not get achievement progress.