Aftermath: Reinforcements from "Hell"

(Default World Types): If you are going to use the DEFAULT, LARGEBIOMES, or anything that is not "Lost Worlds, Lost Worlds (Wasteland)" Keep in mind that the world generation most likely will bug out in some areas! It is not perfect! You will need to tweak the "Cities" generation settings under "More" when creating a new world, to get it to your liking, Tall Buildings and Large cities seem to work the best with Biomes O' Plenty, Tectonic, and Terralith, but you will most likely need to tweak the "Rarity" on the "Cities" Section, The "Floors" section (If your not using Tall Buildings preset), I would also recommend to tweak the height of the buildings to be a little taller to give the extra realism of the cities. And I would HIGHLY recommend to use the "RND" button whilst on the "Transport" section for roads to properly spawn in, aswell as turning down or completely turning off "Vines" under the "Various" section. I will provide my settings aswell. 

Under Cities section

Your map should look like this. 

Under the Buildings section

It should look like this.

Under the Transport section

It should look something like this 

(Lost Worlds): This World Type Generation will only allow for what the World Type provides, which will not include Terralith, Tectonic, Dynamic Trees or any other mods of that matter, It will pratically look like vanilla minecraft with cities.  

F6 Allows you to remove the third person model, this is required for when a gun is in hand or else the first person animations will not work

Q and E to lean left and right

TAB opens inventory

H to inspect weapon or clear jams when needed

C Is used to Crawl

This is a hardcore survival mod, your progess will be different compared to vanilla minecraft, you will need to gather rocks off the ground, and use them to craft cobblestone in order to craft a pickaxe, 4 in a square, once you have stone, you can then use it to mine the abundance of copper around the world, you need copper to mine iron.