Cradle of Humanity allows the player to create the units they want to use in the game. They will start with a basic set of parts, with many more available. As the player progress in the game, they will come against enemies and make allies that have different units and parts. They will be able to interact with the NPC factions to add the parts to their inventory through running missions or removing the parts from a smoldering pile of defeated units if the player is so incline.
These parts can then be added to their units and swap our their old parts. Each part will have different abilities and statistics. Wheels travel faster than tracks, but can't climb rough terrain. Some parts will have more armor, but that will make your unit heavier and take longer to build. Everything in the game is a trade off and a personal preference. Below is a simple animation showing how the parts join together.
The player will assign a unit to a factory, and be able to produce as many different units as they have factories. Adding a certain part may give you a huge advantage while creating a devastating weakness at the same time. A second unit can be developed that offsets the weakness. In this way the player can develop units that can work together, complimenting each other and the player's strategy.