INTRODUCTION
Hey everyone! This guide is part of this video https://youtu.be/E_SceEYMll8 , so I recommend watching that first before diving into the guide.
In this guide, I'll cover the key units you need to understand for positioning,both how to place them and how to play against them. It includes early-game units (1, 2, and 3-cost) as well as late-game units (4 and 5-cost). LETS GET STARTED !!
Units that deal damge to adjacent ennemies






In the early game, make sure your frontline units are not placed next to each other to avoid taking extra damage from th ease units. The same principle applies when you're using one of these units,position them in a way that allows them to hit as many enemies as possible.
Here's an example:

Units that have target stun





Especially if your carry is a frontline unit(darius for example) , try to avoid those units because they have target stun(honestly you cant do much against scar because he have 3unit stun so maybe try to position in a way that you can kill him before he casts) Here's an example:
IMAGE 1 : put another unit to tank zyra stun IMAGE 2 : put all your units in scar side so maybe he dont cast (he needs a lot of mana to cast)
Single target UNITS


Especially if your carry is a frontline unit without a healing item, you need to avoid those units targeting them at the start of the fight, as they could get one-shot too early.

MADDIE
MADDIE targets the farthest unit, so avoid placing your main carry in that position. Instead, adjust your positioning to keep your carry covered. also make sure your strongest tank is in the exact middle hex so he can tank maddie when she casts .


SAME SIDE with ennemy
When should you position on the same side as the enemy?
-against sniper units (kogmaw,zeri) you want to be on the same side so they lose sniper value
-against weak front : If you can kill his frontline before yours falls, position on the same side so your units start attacking his backline before his do.

OPPOSITE side with ennemy
When should you position on the opposite side as the enemy?
-against morgana and swain Since they target the nearest enemies, you want to position your carry farther away from them.
-against strong front :When your frontline falls before his, his backline units will need to move towards yours, giving your units extra seconds to take down his frontline.

These are the units I believe have important positioning in the early game. If you're interested in learning more about late-game units, check out this guide: https://www.tacter.com/tft/guides/positioning-guide-set-13-3259b212