Before We Leave

Easy achievement once you understand how to do it.

Limited Peeps Mode is always off by default when starting a new game. So make sure not to change this.

You need a colony that has advanced far enough that it has researched Shipping in order to build a Shipwright and a port. Once you have a shipwright, build a colony ship and settle another island so a port is now established. Do Not build a school. You don't have to build anything actually once you arrive.

Now build a trade ship. You only need one. This is important and where I could not understand how you could transport peeps on a trade ship at first. DO NOT ATTACH THIS SHIP TO A SHIPPING LANE. Move the ship to your advanced colony's port. Once there, select the ship by pressing A twice. A box appears allowing you to transfer peeps to the ship. Click on Peeps under Port Resources and set the maximum to 30 peeps. Click transfer and the peeps will board. Now travel to the port of the island you want to leave them on. Click on the ship twice with A and select Unload All. All peeps depart.

You will need to make several trips as well as have a big enough population to draw from to get 100 peeps from one island to the other. The peeps need no housing or food on this island for the achievement. There is no happiness requirement either. Achievement pops once the total population of the island reaches 100.

If you have advanced far enough to upgrade your Shipwright to build Large Trade ships, then the maximum peeps they hold is 60.

Hope this helps