Check the orders regularly! These are 3 holographic displays that show what you need to make and how to make it.

If the order requires a plate, use the pink block that has a fork and a knife on it (we'll call this the cooking station from now on). First grab the plate (press E on plate block), place it on the cooking station (press E).
Now grab the ingredients required. Grab the ingredient (i.e. onion), slice it (the block that has a kitchen knife drawn on it), then place it on the cooking station. If it needs another ingredient, repeat this step again.
Grab the finished food and interact with the delivery block (the 2 blocks with triangles on them).

If the order requires 3 of something (for example, onion stew), grab 3 of the ingredient, slice them, then put them on the stove one by one. Wait for it to cook, then grab the food and deliver it.

If the order requires the colliander (for example, the fries), grab the ingredient, slice it, then interact with the colliander block. Wait for it to cook, then grab the food and deliver it.

You can place whatever you've grabbed on the green block that has looping arrows on it. You can then grab it at any time, but the block can only handle having one object on it at a time. You can't put finished food on this block either. But finished food doesn't take up any space (you can hold as many finished foodstuffs as you want + 1 ingredient)

If you messed up, you can put things in the trash bin to get rid of them. Note that you can't recover trashed objects. You also can't trash finished food.

Have fun!