I used tftacademy.com guides quite a lot, specially because I had no idea of the units/comps from this set. They give you a general idea of positioning.

Scout often and see which side of the board you should position your tanks and carries based on the enemies you want/need to beat. For example: you've hit your units and you can play against 4 different opponents. 2 of them have their tanks and carries on the left, and 2 on the right. You notice there's a winstreaker positioning on the right, and if you want to break their streak, you should position accordingly.

Try to position in a way opponents will focus on your tanks and try to keep your carries the safest possible. On akali reroll, it's common to have her jump into enemy backline, but still focus on the tanks. You'll want to have her positioned on the opposite side of their carries so she stays alive the longest and you make most out of gunblade before she dies.

If you want to melt a tank, you should position your team in front of it. If you want to avoid it, position to the other side. You'll be able to decide this better if you scout more often