There will be spoilers, so if you do not want to spoiled...

"Open the handbook for the first time."

Open the brown handbook when you enter the house. It is located on the bottom bookshelf

"Survive for seven years."

Just survive for seven years.

"Meet every human and animal character."

Meet every human and animal.

ANIMALS

• Major
  
• Napoleon
  
• Clover
  
• Benjamin
  
• Squealer
  
• Snowball

All unlocked on Year 1

• ???

I am unsure how this animal is found

• Boxer
  
• Mollie
  
• Sheep
  
• Cat
  
• Cows
  
• Dogs

All unlocked on Year 1

• Goose

I am unsure how the goose arrives

• Hens
  
• Rats

All unlocked on Year 1

• Birds

All unlocked on Year 1

• Camel

The Camel arrives with the travelling circus, To have him on Animal Farm, approve him with Boxer.

HUMANS

• Whymper

Mr Whymper is unlocked by trade, Benjamin says that there will be no one to make nails dog biscuits, iron for horseshoes, etc

• Pilkington

Pilkington is introduced in year 1 alongside Frederick on the last day of autumn and the first day of winter via a cut-scene

• Jones

All unlocked on Year 1

• Frederick

Frederick is introduced in year 1 alongside Pilkington on the last day of autumn and the first day of winter via a cut-scene

"Reach every ending."

• Starvation

Have no supplies during winter and cannot get more.

• Betrayal

When you run out of food you have an option to give up, choose to give up and choose Comply

• Depopulation

Have enough animals die from battles, being chased off, or poorly maintained buildings

• Takeover

Lose a battle

• Cabal of Pigs

Have Napoleon and Snowball alive at the end (year 7)

• Squealer's Victory

Snowball and Napoleon are both dead for Squealer to rule over Animal Farm

• Snowball's Victory

Napoleon dies or left Animal Farm

• Napoleon's Victory

Snowball dies or left Animal Farm

"Collect every stamp."

Most of the stamps of descriptions on how to achieve them, if you still are having trouble, read this good guide on how to find all the stamps is the guide by Mccoy https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2483165384