Hearts of Iron IV - The Puppetmaster Achievement Guide

This guide is not very detailed, but i hope it helps.

How to Obtain The Puppetmaster Achievement

The Puppetmaster

For people with over 50+ hrs

If you have 50+ hours, you should be able to follow these steps without a problem.

Start as Britian in 1936.
Join axis.
Now declare war on France.
Liberate their colonies.
Now, im not sure if the colonies become your puppets. In case they don’t declare war on each one of them.
Now delcare war on Italy.
Liberate their colonies.
Same thing with France.
That should be about 40 puppets. To get more puppets, release your occupied nations and declare war on them.
After you win, puppet them.
If you don’t have 51 puppets by now, declare war on some minor nations.
And you should get the achievement.

For people with 25+ hours

Detailed explanation of naval invasion and steps.

Start as Britian.
Join axis (can be done with focus or by placing a facist advisor).
Justify war goal against France.
Select some of your ships and select “naval invasion support” then right click on the region you want.
Create a new army (max 10 troops).
Place a general.
Select naval invasion and select one of your dockyards, then right click on an enemy territory.
Wait 70 days.
Declare war and start the naval invasion (you can also call your allies to help you).
After you win, you will be greeted with peace conference.
Liberate their colonies.
Now, im not sure if the colonies become your puppets. In case they don’t declare war on each one of them.
Declare war on Italy.
Same thing with France.
Release occupied nations then delcare war on them.
If you don’t have 51 puppets by now,declare war on some minor nations.
And you should get the achievement.

Good luck,and i hope this guide helped.