Import read your save data and write it on top of newly generated world
It is a world recreation process that fix the issues with changes in the game and preserve your progress

Import Fix and improve mods compatibility with your world data
Reset missing NPCes if they are not dead
Reset Dialogues and interactions like they never happened
Reset Raids and raid counters and few mechanics around it
Reset shops all around the world and memory of your crimes
Can reduce load time of your saves (lowers size of future save files)

• upon installation of new mod
  
• Agnu didn't spawn again...
  
• I can't even enter this stupid thing and reload or shift + ctrl + f11 didn't helped
  
• After removal of sizeable mods that had hidden bugs
  
• Once game updated to a version with major changes (might never happen again according to Lo-fi Community lead)
  
• If you experimented with mods or modified world/save on your own

• Load your game as it is
  
• Take your selected people outside of the buildings (optional)
  
• Save the game and create new save for it
  
• Quit the game completely (import can be done only from the menu)
  
• Change modlist, sort load order, remove bad mods, add my mods xD.
  
• You should be ready for import

This function pull all your characters to the location of your camera
Function is safe to use, but for import you wanna have people in their respective zones
You can safety reset squad position with reloading the game when someone get stuck

• Off means game will treat the world like you never build or bought anything, yours every chest or fence get deleted with everything inside (not exactly deleted, but simplifications are needed)
  
• On means game will preserve data about what you created and which buildings you purchased

• ON - you keep your data
  
• OFF - return to the monke

• ON - game remember which factions you damaged/destroyed
  
• OFF - world reset to the form as you was never there

A lot of people have problem with understanding this one option, i hope this make it clear

• ON - you preserve all your alliances and enemies
  
• OFF - everything goes back to default (0 for civilized factions), can be useful for tech hunters or other factions that you pieced off, but there are better options for reset relation of 1 faction

And here we are, welcome in funzone - All values on image are default states

Time it takes for your person to get hungry

• 1.0 is default and on default Greenlander needs 25.28 Nu for a day
  
• 0.1 means you will need 250 Nu per day!
  
• 2,0 means you will need 12.5 Nu per day

Everything on hunger is super expanded in my funny calculator that i might link at the bottom
This value influence how fast wounds get worse and how fast people bleed (this influence everyone, not just the player)
Default is value of 1 is pretty good - if you die with it, its because you need to learn the game, not rig it
Increasing this value increase difficulty for humanoid characters and makes medkits more important
i like it with 1.0 i often see default settings as game was designed around them
don't see 2,0+ as harder, rather encourage cheesy strategies or low level play (running away, crossbows, kiting),
it makes defense more important, but i rather recommend x3 attack slots instead

• Time to harvest water or iron
  
• Time to cook food
  
• Time to craft Chainmails (eternity on default)
  
• Influence automatic machines not just humans

Making it faster trivialize earlygame, but greatly improve mid/endgame (subjective opinion)
Cons of making it faster:

• Your Scientist will grind less stats during research (can still get 90 skill if 1 dude do all research)
  
• If you see incoming raid you might try something funny like researching harpoons before they get to you

i believe making it faster might overall make building a base more fun, you still need materials to advance the researches so alone x3.0 should not harm your experience
Building speed not just affect how fast you build things, but also how fast you repair
and when used for gate repairing makes single person very good at holding the door xD
Outside of this one usage, its rather improve experience with the game (subjective opinion)
it mostly change spawns like dust bandit camps, spider nests, beak things nest or others
game still wants nest to stand apart from each other which might increase number of empty nests
This option can turn game into dense fighting mess in some zones, rather for fun run than serious longplay
This allow bandits to take your weapons, food and rarely equipment
Bandits can loot very few items and even with this on, you don't risk much
i would say this option is fair to have on all the time regardless of your playtime
game suggest it will make prospecting option in gameplay act like everyone would have same science level, but it doesn't do anything
Scientist still see bigger circle than farmer
On default this option is OFF

I hope this guide will be informative enough for new players and might even give veterans few hints
if you knew everything i included in the guide i m very happy for you, but now you can send it to someone who didn't and hopefully help them this way
Import button is pretty useful mechanic and don't be afraid to use it


My stuffs if you care about it:
Optimization guide:
https://kenshi-modding.fandom.com/wiki/Kenshi_Modding_Wiki:SCAR%27S_Performance_Optimization_Guide
Kenshi mods:
https://www.nexusmods.com/kenshi/users/16691049
Reverse engineering game mechanics in form of google excel tables
(i call it google excel, because it is and to make google fans mad xD)
https://docs.google.com/spreadsheets/d/1pvr2X3ua34ItW2y-t9HlJFHKAp2o1y564tkqLvIgQNY/edit#gid=1155402122
Have fun in Kenshi