Sorry it's not entirely clear what some things do! I admit that the help menu wasn't fully completed. Here's a quick breakdown if you decide to give it another go.
There are three types of things you can build in the game.
1. Gatherers (Open square with big corners.) These will pull shapes that are on the ground and make copies.
2. Machines (Filled square with 4 dots.) These will take in shapes and do something to them. Cutting them in half, joining two shapes together, coloring them, etc. You start out with none unlocked and unlock one each level until all are unlocked. Each new machine in the early levels will make the requested shape either possible to make, or much easier to make. The help menu shows what each of the machines do to an input.
3. Conveyors (Look like an orange W in build menu.) These connect everything together. Gatherers to machines, machines to other machines, etc.